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THE  x4NAT0MY  AND  PATHOLOGY 
OF  THE  TEETH. 


BY 


C.  F.  W.  BODECKER,  D.D.S.,  M.D.S. 


With   Three  Hundred  and  Twenty-five  Illustrations. 


Adopted  by  the  National  Associatiox  of  Dental  Faculties 
AS  A  Text-Book  foe  Dental  Students. 


PHILADELPHIA: 

THE   S.  S.  WHITE    DENTAL   MANUFACTURING   CO. 

1894. 


\ 


Copyriglit.  1894,  by  C.  F.  W.  Bodecker. 


TO    HIS 
HIGHLY    ESTEEMED    TEACHER  AND   FRIEND, 

Carl  Heitzmann,  M.D., 

THIS  BOOK  IS  DEDICATED    BY  THE 
AUTHOR. 


PREFACE. 


TXy  HEX,  nearly  eighteen  years  ago,  I  first  entered  the  hibora- 
V  y  tory  of  Dr.  Carl  Heitzmann  and  listened  to  his  lectures 
on  general  histology,  I  became  so  thoroughly  imbued  with  the 
conviction  of  the  correctness  of  his  views  that  I  resolved  to  study 
the  tissues  building  up  the  teetli  in  the  light  of  the  novel  doc- 
trine. Ever  since  I  have  been  a  faithful  attendant  at  his  labora- 
tory. Besides  myself,  hundreds  of  dentists  have  attended 
that  institution,  largely  owing  to  the  enthusiastic  impulse  of 
my  much-lamented  friend,  the  late  Dr.  William  H.  Atkinson. 
As  a  consequence,  a  number  of  these  gentlemen,  including 
Professor  Frank  Abbott,  Dr.  William  H.  Atkinson,  Dr.  John 
I.  Hart,  and  Dr.  F,  A.  Roy,  have  enriched  dental  literature  with 
the  results  of  original  investigatioui^,  made  in  the  same  labora- 
tory, all  of  which  will  be  found  embodied  in  this  book. 

So  long  as  the  cell-theory  holds  sway  over  the  minds  of  the 
majority  of  microscopists,  the  views  here  laid  down  cannot  meet 
with  general  acceptance.  As  early  as  1859  no  less  a  man  than 
Thomas  H.  Huxley  declared  that  the  history  of  the  develop- 
ment of  the  teeth  was  not  intelligible  upon  the  grounds  of  the 
cell-theory.  We  to-day  can  state  that  neither  the  normal  nor 
the  morbid  anatomy  of  the  tissues  is  explicable  on  the  basis 
of  that  theory.  How  long  it  will  be  before  the  novel  views 
advanced  by  Dr.  Carl  Heitzmann,  and  which  are  directly  antag- 
onistic to  the  cell-theory,  will  gain  a  final  victory  it  is  impossible 
to  foretell.  In  our  time  discoveries  are  made  in  rapid  succession  : 
some  are  at  once  accepted,  to  be  discarded  later  upon  more 
critical  investigation;    others,  which  meet  with  incredulity  or 


viii  I'REFACE. 

open  .loniul  at  lirst,  prevail  in  the  long  run,  as  they  must  do  if 
verified  by  honest  observations  and  facts.  It  is  gratifying  to 
my  liighly-esteemed  friend  and  teacher  to  know  that  already  a 
number  of  independent  observers  have  indorsed  his  views.  It 
is  true  he  has  not  escaped  the  criticism,  even  enmity,  which 
ai)pear  to  be  the  lot  of  every  daring  original  investigator ;  hut 
while  opposition  may  delay  the  acknowledgment  of  these  newly- 
interpreted  fiicts,  it  will  not  be  able  to  prevent  their  ultimate 
acceptance. 

I  cheerfully  acknowledge  the  great  assistance  rendered  me  by 
Dr.  Carl  Heitzmann  in  the  preparation  of  this  book.  To  him 
I  am  indebted  not  only  for  the  artistic  illustrations,  which  were 
all  made  by  him,  but  also  for  aid  in  the  microscopical  researches, 
both  those  previously  published  and  those  here  set  forth  for  the 
first  time. 

While  the  minds  of  the  majority  of  American  dentists  are 
largely  directed  toward  so-called  practical  topics,  I  yet  hope 
that  no  intelligent  dental  practitioner — and  this  work  has  been 
written  only  for  such — will  lay  aside  the  book,  after  its  con- 
scientious perusal,  without  feeling  that  he  has  gained  some 
additional  knowledge  fi'om  it.  I  ask  only  unbiased,  conscientious 
reading.  I  know  that  our  profession  is  not  lacking  in  students 
competent  and  willing  to  give  this,  and  to  them  I  trust  the 
verdict  as  to  the  value  of  my  labors. 

This  book  may  help  in  demonstrating  that  scientific  investi- 
gations are  not  neglected  in  our  country.  Its  preparation  has 
cost  all  my  leisure  time  during  almost  a  decade ;  but  if  its  publi- 
cation shall  prove  of  service  to  my  profession,  I  shall  feel  more 
than  repaid. 

Carl  F.  W.  Bodecker. 

Nkw  York,  July,  1894. 


CONTENTS. 


PAGE 

CHAPTER   I. 
The  Superior  Maxillary  Bones 1 

CHAPTER  II. 
The  Inferior  Maxillary  Bone         .         . 9 

CHAPTER  III. 
The  Teeth 16 

CHAPTER   IV. 

Individual  Characteristics  of  the  Teeth 24 

CHAPTER  V. 

The  Pulp-Chambers  of  the  Teeth 28 

CHAPTER   VI. 
The  Articulation  op  the  Teeth 84 

CHAPTER  VII. 
General  Anatomy  of  the  Human  Teeth 39 

CHAPTER   VIII. 
General  Histology 46 

CHAPTER  IX. 
Development  of  Connective  Tissue 58 

CHAPTER   X. 
The  Minute  Structure  of  Dentine 69 

CHAPTER   XL 
The  Minute  Structure  of  Enamel 90 

CHAPTER   XII. 
The  Minute  Structure  of  Cementum .101 

CHAPTER  XIII. 
Synopsis  of  the  Development  of  the  Teeth 124 

CHAPTER  XIV. 
Development  of  Dentine .         .  129 


X  CONTENTS. 

OH  APT  Ell    XV.  I'AGK 

DkVKLOI'MKNT  of  TlIK   Knamki-    .........    148 

(Ml  A  I'T  K  K    XVI. 
F-vri-TY  Dkvki.opmknt  ........   194 

CHAPTEK   XVI 1. 
Devklopmknt  ok  Ckmkxtum 227 

CHAPTER   XVIII. 
The   Dkvkloi'.mknt  of  Teeth  in  Embryos  affected  with    IIhachitis  232 

CHAPTER   XIX. 
The  Dental  Pulp 244 

CHAPTER   XX. 
The  Pericementlm 256 

CHAPTER   XXI. 
Eruption  of  the  Teeth 261 

CHAPTER   XXII. 
Absorption  of  Temporary  Teeth 264 

CHAPTER   XXIII. 
Phy'siology  of  the  Hard  Dental  Tissues 270 

CHAPTER   XXIV. 
General  Diagnosis  of  the  Diseases  of  the  Teeth       ....  274 

CHAPTER   XXV. 
Irritation  and  Kew  Formations  of  Dental  Tissue      ....  288 

CHAPTER   XXVI. 
Secondary  Dentine 292 

CHAPTER   XXVII. 
Mechanical  Abrasion 309 

CHAPTER   XXVII  I. 
Erosion 816 

CHAPTER  XXIX. 
The  Reaction  of  the  Dentine  upon  Fillings 320 

CHAPTER   XXX. 
Hyperostosis  of  Roots  of  Teeth 329 

CHAPTER   XXXI. 
Inflammation 34g 

CHAPTER   XXXII. 
Inflammation  of  the  Gums, — LIlitis        . 3g3 


CONTENTS.  XI 


PAGE 


CH  APTER   :^  XXIII. 
Inflammation  of  Dentine, — Eburnitis     .......  370 

CHAPTER    XXXIV. 
Pulpitis  in  its  Clinical  Aspects 380 

CHxVPTER   XXXV. 
Morbid  Anatomy  of  Pulpitis 397 

CHAPTER    XXXVI. 
Degenerations  and  Atrophies  of  the  Pulp 412 

CHAPTER    XXXVII. 

Morbid  Anatomy  of  Atrophies  and  Degenerations  of  the  Pulp      .  420 

CHAPTER   XXXVIII. 
Pericementitis  in  its  Clinical  Aspect 432 

CHAPTER   XXXIX. 
Morbid  Anatomy'  of  Pericementitis 462 

CHAPTER   XL. 
Caries  of  the  Teeth 488 

CHAPTER  XL  I. 

The  Effects  of  Arsenic  Dioxide  and  Metallic  Arsenic  upon  the 

Pulps  of  the  Teeth,— So-Called  Coagulation-Necrosis        .         .  518 

CHAPTER   XLII. 
Necrosis  of  the  Jaw-Bones 534 

CHAPTER  XLIII. 
Empyema  of  the  Antrum 542 

CHAPTER  XLIV. 

The  Clinical  and  Anatomical  Features  of  Tumors  in  General      .  546 

CHAPTER  XLV. 
Tumors  of  the  Teeth 553 

CHAPTER  XLVI. 
Cy'sts  in  the  Oral  Cavity 559 

CHAPTER    XLVIL 
Tumors  of  the  Jaws 573 

CHAPTER   XL  VI II. 
Malformations  and  Malpositions  of  the  Teeth 609 

LITERATURE 614 

INDEX 669 


The  Anatomy  and  Pathology  of  the  Teeth. 


CHAPTEE    I. 

THE  SUPERIOR  MAXILLARY  BONES. 

To  the  dental  practitioner  these  bones,  together  with  the  lower 
jaw-bone,  are  the  most  important  ones  of  the  human  body. 
They  occupy  the  central  region  of  the  face,  on  either  side  of 
the  nasal  cavities,  and  each  of  them,  in  a  normal  condition, 
is  mounted  with  eight  teeth.  In  connection  with  the  other 
facial  and  cranial  bones,  they  constitute  the  frame-work  of  the 
upper  and  greater  part  of  the  face.  Each  superior  maxillary 
contributes  to  the  formation  of  the  roof  of  the  mouth ;  to  the 
floor  and  outer  walls  of  the  nasal  cavities,  as  well  as  to  the  floors 
of  the  orbits.  Aside  from  the  /xvi/y,  which  is  somewhat  cuboidal 
in  shape,  Ave  distinguish  four  processes, — i.e.,  the  malar,  the  nasal, 
the  palatine,  and  the  alveolar  ]>rocess.  The  bodj^  of  this  bone  con- 
tains a  large  cavity,  the  antrum  of  Wghmore,  obviously  for  the 
purpose  of  minimizing  the  weight  of  the  bone,  and  at  the  same 
time  of  increasing  its  proportionate  strength. 

The  external  or  facial  surface  (Fig.  1)  shows  above  the  incisor 
teeth  a  slight  depression,  called  the  incisive  fossa.  Outward  from 
this  is  another  depression,  the  canine  fossa,  which  is  deeper  than 
the  incisive,  and  separated  from  it  by  a  vertical  ridge,  the  canine 
eminence,  corresponding  to  the  socket  of  the  canine  or  cuspid 
tooth.  At  the  upper  portion  of  the  canine  fossa  we  observe  the 
infra-orhital  foramen,  through  which  pass  the  infra-orbital  nerve 
and  artery. 

The  posterior  or  zygomatic  surface  is  pierced  by  several  aper- 
tures, the  orifices  of  the  j^osterior  dental  canals,  for  the  transmis- 
sion of  the  posterior  dental  vessels  and  nerves.     The  lower  part 

2  1 


1:  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

of  the  /ygoniatii.'  surface  gradually  develops  into  the  ma:rlllary 
(iihirosit;!,  which  is  most  conspicuous  after  the  eruption  of  the 
wisdom  or  third  molar  tooth. 

The  superior  or  orbital  surface  is  made  up  of  a  thin  triangular 
plate  of  bone.  It  is  traversed  by  the  iitfra-orhitai groove,  carryings 
the  infra-orbital  nerve  and  artery.  This  groove  terminates  in  a 
canal,  dividing  into  two  branches ;  one  of  which,  the  wfra-orhital, 
opens  l:)elow  the  border  of  the  orbit,  while  the  other,  Avhich  is- 
smaller,  pierces  the  anterior  wall  of  the  antrum,  and  bears  the 
name  of  anfcrior  denial  camd,  transmitting  the  anterior  dental 
vessels  and  nerve  to  the  front  teeth. 


Fiu.   1. 


ExTERSAL  OR  Facial  Scrface  op  the  Right  Superior  Maxillary  Boxe. 

/,  Incisive  fossa  :  t',  canine  fossa  :  £,  canine  eminence  :  F,  iufra-oibital  foramen  ;  P,  posterior- 
dental  canals:  G,  infra-orbital  groove;  ,1/,  malar  process. 

The  /mdar  proce.-<.^  is  a  prominent  rough  eminence  servino-  for 
the  articulation  with  the  malar  bone.  The  descending  ridge 
constitutes  the  boundary  between  the  facial  and  zygomatic  siu'- 
faces.  ^  From  this  ridge  a  small  portion  of  the  masseter  muscle 
takes  its  origin. 

The  nasal  process,  directed  upward,  has  a  concave  external  sur- 
face. The  anterior  border  of  this  process  articulates  Avith  the 
nasal  bones ;  the  posterior  is  hollowed  out  by  a  o-roove  in  which 
the  lachrymal  duct  lodges.     This  groove  is  converted  into  a 


THE    SUPERIOR    MAXILLARY    BONES.  3 

canal  by  the  lachrymal  and  a  part  of  the  inferior  turbinated 
bones. 

The  palate  process  (see  Fig,  2)  is  a  strong  piece  of  bone  project- 
ing horizontally  from  the  inner  surface  of  the  superior  maxilla. 
It  is  especially  thick  anteriorly,  the  upper  surface  forming  a  large 
portion  of  the  Hoor  of  the  nasal  cavity,  while  the  lower  surface 
makes  up  the  greater  portion  of  the  roof  of  the  oral  cavity. 
The  lower  surface  is  slightly  concave,  and  is  channeled  at  the 
posterior  part  of  its  alveolar  border  for  the  passage  of  the  pos- 
terior palatine  vessels  and  the   anterior  and   external  palatine 

Fig.  2. 


IxFERiaR  Surface  of  the  Right  Scpeeior  Maxillary  Boxe. 

P,  palate  proaess:    S,  anterior  nasal  spine;    A,  opening  of  antrum:   .1/,  lower  meatus  of 
nasal  cavity  ;  L,  laehr3-mal  groove. 


nerves.  The  two  palate  processes  assist  in  forming  an  orifice 
in  the  median  line,  the  anterior  palatine  canal  This  canal  is 
divided  into  four  compartments,  two  of  which  run  laterally  to 
the  right  and  left  nasal  fossae,  while  the  anterior  and  posterior 
compartments  run  along  the  median  line.  The  anterior  one 
serves  for  the  transmission  of  the  anterior  branch  of  the  descend- 
ing palatine  arteries.  The  anterior  and  the  posterior  compart- 
ments transmitthe  naso-palatine  nerves,  the  left  running  through 
the  anterior,  the  right  through  the  posterior  canals.  The  roof 
of  the  mouth  is  pierced  by  a  number  of  small  canals  which 


THE    ANATOMY    AND    I'ATIIOLOCiY    OF   THE    TEETH. 


carry  the  vessels  for  the  nutrition  of  the  bone.  The  upper  sur- 
face of  the  palate  process  is  concave  and  smooth,  exhibiting  the 
openings  of  the  canals  above  mentioned.  The  inner  border  of 
the  palate  process  is  raised  into  a  central  ridge  which  supplies  a 
space  of  attachment  to  the  vomer.  Anteriorly,  this  process  pro- 
duces a  sharp  prolongation,  the  mdcrior  nasal  spine.  The  pos- 
terior border  serves  for  articulation  with  the  palate  bone.  The 
upper  portion  of  this  surface  shows  a  large,  irregular  opening, 
that  o-f  the  antrum.  The  upper  border  of  the  opening  is  par- 
tially closed  by  the  cellular  cavities  of  the  ethmoid  bone. 
Below  this  opening  a  smooth  concave  surface  presents  itself, 
the  Inirer  meatus  of  fhe  nasal  eaelUj.  Behind  the  opening  we 
notice  a  rough  surface  that  articulates  with  the  perpendicular 

Fig.  3. 


The  Alveolar  I'hocess  ok  the  Right  Slperior  Maxillaky  Bone.    View  from  Below 

IS  Natural  Size. 

plate  of  the  palate  bone,  being  traversed  by  a  groove  which, 
with  a  corresponding  portion  of  the  adjacent  palate  bone,  forms 
the  posterior  palatjm  canal,  directed  obliquely  downward  and  for- 
ward. In  front  of  the  opening  of  the  antrum  a  groove  is  seen, 
which  with  the  lachrymal  and  inferior  turlnnated  bones  consti- 
tutes the  lachrymal  or  nasal  duet.  At  the  base  of  the  nasal  pro- 
cess is  the  horizohtal  or  inferior  turbinated  crest  for  the  articulation 
of  this  process  with  the  inferior  turljinated  bone.  The  wall  of 
the  inferior  meatus  of  the  nasal  cavity  is  perforated  by  numer- 
ous small  foramina,  which  serve  as  carriers  of  nutrient  vessels. 
The  alveolar  process  is  the  portion  of  the  jaw  which  holds  the 
teeth.  It  contains  eight  excavations  or  sockets  for  this  purpose 
(Fig.  3).     The  deepest  of  these  excavations  is  the  socket  of  the 


THE    SUPERIOR    MAXILLARY    BOXES.  5 

canine  or  cuspid  tooth  ;  the  sockets  of  the  molars  are  the  widest, 
and  are  usually  subdivided  into  three  smaller  cavities,  corre- 
sponding in  number  with  the  roots  of  the  teeth.  The  socket 
of  the  third  molar  is  usually  single,  while  that  of  the  first 
bicuspid  exhibits  two  cavities,  and  that  of  the  second  bicuspid 
usually  but  one.  The  sockets  for  the  incisors  are  always  single. 
They  are  of  roundish  form  for  the  central,  but  for  the  lateral 
incisors  the  sides  of  the  receptacles  are  somewhat  compressed. 

The  ant r II III  is  the  largest  of  the  so-called  pneumatic  spaces 
of  the  skull.  It  is  a  cavity  of  four  surfaces, — the  upper  or  orbital 
surface ;  the  posterior  surface,  produced  by  the  maxillary  tuber- 
osity ;  the  anterior  or  facial  surface,  which  is  slightly  depressed 
bv  the  canine  fossa;  and  the  inner  or  nasal  surface.  When 
regularly  formed,  the  antrum  has  the  shape  of  a  triangular 
pyramid,  and  either  the  upper  orbital  or  the  inner  nasal  sur- 
face may  be  considered  the  base  of  the  pyramid.  The  inner 
wall  of  the  antrum  is  divided  by  the  articulation  of  the  turbi- 
nated bone  into  an  upper  and  a  lower  half  (pars  supra-  and  pars 
infra-tarbinalis).  The  lower  half  is  made  up  anteriorly  by  the 
superior  maxillary,  and  posteriorly  by  the  vertical  lamella  of  the 
palate  bone.  The  upper  half  is  supplied  with  several  openings, 
which  are  quite  large  in  the  skeleton,  but  much  smaller  in  the 
vital  state,  in  which  condition  the  bones  are  covered  by  their 
lining  membrane.  If  the  mucous  covering  closes  these  gaps, 
such  membranous  portions  Zuckerkandl*  terms  fontanelles.  Of 
these,  he  designates  one  as  anterior  and  one  as  posterior.  There 
is  left  only  a  longitudinal  opening,  the  ostium  maxillare,  within 
the  unciform  process  of  the  ethmoid  bone,  and  one  ethmoidal 
cell,  invested  by  a  mucous  membrane,  communicating  with  the 
frontal  sinus  and  the  nasal  cavity.  The  lower  surface  or  floor 
of  the  antrum  is  formed  by  a  thin  bony  plate.  Between  this 
and  the  alveoli  of  the  teeth  is  a  layer  of  spongy  bone.  The 
latter  substance,  as  a  rule,  is  thinnest  over  the  roots  of  the  molar 
teeth.  The  roots  of  the  incisor  teeth  are  not  within  the  boundary 
of  the  antrum.  The  canine  and  the  first  bicuspid,  though  near 
the  floor  of  the  antrum,  do  not  quite  reach  it,  the  floor  being 
overlaid  by  a  bulky  osseous  structure.  The  apices  of  the  roots 
of  the  second  bicuspid  and  the  buccal  roots  of  the  molars  are 
in  contact  with  the  floor  of  the  antrum.     The  second  bicuspid 

*]Srormale  unci  Patholoffische  Anatoniie  der  jSTasenhole.     Wien,  1882. 


6 


THE    ANATOMY    AND    PATHOLOGY    OF   THE    TEETH. 


an.l  tlie  first  molar,  as  a  rule,  correspond  to  the  deepest  portion 
of  the  antrum. 

Variations  in  the  Size  of  Antra. — The  difterence  in  size  of 
the  upi-er  jaws  of  various  individuals  is  not  great,  but  of  the 
antra  the  shapes  and  sizes  vary  considerably ;  nay,  sometimes 
there  are  marked  differences  in  the  two  antra  of  the  same  head. 

Zuckerkandl  publishes  the  following  table  of  variations  in 
the  size  of  antra,  some  of  the  figures  of  this  table  being  quoted 
from  C.  Reschreiters : 


Heights  of 
Upper  Jaw?. 

Heights                     Breadths                     Depths 
of  Antra  given  in  Millimeters. 

64 

19 

25 

21 

64 

29 

25 

21 

64 

32 

28 

83 

64 

32 

25 

34 

64 

32 

24 

32 

64 

38 

22 

34 

64 

39 

25 

SO 

56 

13 

15 

14 

59 

37 

29 

18 

Communication  between  the  Antrum  and  the  Nasal  Cavity. — 
The  opening  termed  ostiojii  ma.rjjlart  is  situated  in  the  middle 
meatus  of  the  nose.  It  leads  into  the  hiatus  semilunaris  in  com- 
pany with  the  ostium  fronUde,  which  communicates  with  the 
frontal  sinus  (see  Fig.  4).  The  latter  is  situated  superficially  in 
the  frontal  portion,  while  the  ostium  maxillare  lodges  backward 
and  is  somewhat  hidden  in  the  infundibulum.  The  best  view 
of  the  ostium  maxillare  is  obtained  from  the  antrum  (see  Fig. 
5,  M),  where  Ave  observe  it  a  little  below  the  orbital  surface, 
on  the  upper  border  of  the  nasal  surface  of  the  antrum.  Its 
shape  is  irregular,  most  frequently  semilunar,  but  often  oval, 
and  sometimes  round.  According  to  Zuckerkandl,  this  opening 
varies  from  three  to  nineteen  millimeters  in  length,  and  from 
three  to  five  millimeters  in  breadth.  Sometimes  there  exists, 
between  the  antrum  and  the  nose,  an  accessory  communication, 
which  is  usually  small  and  round  (see  Fig.  5,  A).  This  acces- 
sory opening  generally  is  situated  in  the  posterior  fontanelle, 
somewhat  lower  than  the  ostium  maxillare.  In  rare  instances 
the  communication  bet^veen  the  antrum  and  the  nasal  cavity  is 
closed,  the  result  either  of  a  chronic  infiammatory  process  or 
of  a  malformation  during  development. 


THE    SUPERIOR    MAXILLARY    BONES. 


The  Lining  Membrane  of  the  Antrum  has  a  double  function, 
— i.e.,  it  serves  as  a  periosteal  cover,  supplying  the  nutritive 
vessels  to  the  bony  walls  of  the  cavity,  and  at  the  same  time 
secretes  mucus.  It  is  continuous  with  the  mucous  lining  of  the 
nasal  cavity,  and  is  closely  adapted  to  the  depressions  and  eleva- 
tions in  the  bony  wall  of  this  cavity.  According  to  Sappey,  the 
mucosa  of  the  antrum  is  supplied  with  glands,  which  in  appear- 
ance are  much  like  the  Meibomian  glands  of  the  eyelids.     They 


Sagittal  Section  through  the  Xasal  and  Oral  Cavities,  partly  after  Zuckee- 

KAVDL. 

H,  semilunar  hiatus  ;  U,  upper  lip,  the  ethmoidal  bulla  ;  L,  lowpr  lip,  the  unciform  process ; 
M.  insertion  of  middle  turbinated  bone ;  T,  lower  turbinated  bone ;  E,  mouth  of  Eustachian 
tube. 

are  irregularly  distributed,  and  much  scantier  than  those  of  other 
mucous  membranes. 

The  antrum  is  supplied  with  blood-vessels,  principally  derived 
from  the  mucous  membrane  of  the  nasal  cavity,  although  some 
of  the  smaller  branches  arise  fi-om  the  posterior  dental  arteries 
through  the  alveoli. 


8 


THE    ANATOMY    AND    rATIIOLCxiY    OF    THE    TEETH. 


Development. — The  superior  maxilla  is  one  of  the  earliest 
bony  formations,  and,  as  anatomists  suppose,  it  starts  from  four 
centers  of  ealcitication,  namely :  the  j^'cmoxilUm/,  the  palatine, 
the  /na.rillaiy,  and  the  inalar  portions.  With  the  exception  of  the 
maxillary  portion,  all  these  develop  from  and  around  hyaline 
eartilair-e.     The  prcmaxilla,  to  the  presence  of  which  the  great 


LKFr  Slpebior  Maxillary  Bone,   kxhibiting  thk   Commumcatioxs  between  Aktkum 
AND  Nasal  Cavity.    (After  Zuckeekaxdl.) 

O.orbital  cavity;   i/,  maxillary  cavity  or  antrum  of  Highmore ;   M,  slit-like  opening  or 
ostium  maxillare;  A,  accessory  opening  between  antrum  and  nasal  cavity. 

German  philosopher  and  poet,  Goethe,  first  drew  attention,  holds 
the  two  incisor  teeth  on  each  side.  In  young  subjects  its  articu- 
lation with  the  palatine  portion  is  still  visible.  In  the  eon- 
genital  malformation  of  the  upper  jaw  termed  deft  palate,  this 
portion  is  separated  from  the  remainder  of  the  maxillary  bone 
by  a  single  or  double  fissure,  usually  associated  with  a  corre- 
sponding fissure  of  the  upper  lip,  called  hare-lip.    - 


THE    INFERIOR    MAXILLARY    BONE.  \) 

The  antrum  begins  to  develop  in  the  maxillary  portion  of  the 
bone  at  about  the  fourth  month  of  fcetal  life. 

Involution.'^ — By  this  term  is  indicated  a  retrograde  change 
leading  to  a  partial  or  complete  disappearance  of  tissues  and 
organs.  It  is  of  frequent  occurrence  in  embryonal  develop- 
ment, the  same  as  in  senile  reduction  of  the  size  of  organs, 
especially  that  of  the  skeleton,  whereby  bone-tissue  is  brought 
back  to  iibrous  and  myxomatous  tissue  preceding  absorption. 

The  studies  of  the  authors  herein  named  were  made  on  the 
upper  jaw  of  a  woman  who  died  when  seventy-five  years  of  age. 
The  thickness  of  this  jaw,  between  the  oral  and  the  nasal  cavi- 
ties, was  not  more  than  from  four  to  five  millimeters.  The  sur- 
face of  the  oral  cavity  was  perfectly  smooth,  without  a  trace  of 
a  tooth  or  socket.  The  bone  was  present  only  in  thin  ledges, 
arranged  in  an  irregular  line,  and  without  distinction  between 
the  compact  and  the  cancellous  structures.  Xumerous  pieces 
of  hyaline  cartilage  were  present  in  the  same  stratum  with  the 
bony  tissue,  which  proves  that  the  cartilage  grows  from  a  pre- 
vious bony  structure,  and  that  it  replaces  the  latter. 


CHAPTER    II. 

THE  INFERIOR  MAXILLARY  BOXE. 

This  is  the  largest  bone,  and  the  only  movable  one,  of  all  the 
facial  bones.  It  consists  of  a  horizontal  hody  and  Ul-q  perpendicu- 
lar -projections,  the  '/■«//(/,,  arising  from  the  body  nearly  at  right 
angles  to  it. 

The  body  presents  for  examination  two  surfaces,  the  external 
and  the  internal ;  and  two  borders,  the  alceolar  and  the  inferior. 
The  external  surface  (see  Fig.  6)  is  convex  from  the  median  line 
to  the  ramus,  and  slightly  concave  from  above  downward.  In 
the  middle  line  we  observe  a  shallow  vertical  ridge,  indicative  of 
the  junction  of  the  two  pieces  of  bone  from  which  the  body  de- 
velops. The  ridge  terminates  below  in  a  protrusion  termed  the 
mental  process.  Outward  of  this  central  ridge  is  a  slight  depres- 
sion, the  incisive  fossa.     Farther   backward   we   find  the  large 

*  "  Senile  Atrophy  of  the  Upper  .Jaw.  - '  By  Carl  Heitzmann  and  Frank  Abbott. 
Dental  Cosmos,  1892. 


10 


THE   ANATOMY    AND    PATHOLOGY    OF    THE   TEETH. 


mental  foramen  for  the  transmission  of  the  mental  nerve  and 
artery.  The  location  of  this  foramen  corresponds  with  the  in- 
terstice l)et\veen  the  roots  of  the  first  and  second  bicuspid  teeth. 
Posterior  to  this  foramen  begins  a  carved  ridge,  the  external 
oblafuc  V.iie,  which  runs  backward  and  upward,  being  continuous 
with  the  anterior  border  of  the  ramus. 

The  alveolar  process  is  more  massive  posteriorly  than  in  its 
anterior  portion.  It  is  pierced  by  sixteen  sockets  for  the  recep- 
tion of  the  teeth. 

The  inferior  border  of  the  body  is  rounded  and  quite  massive 
anteriorly;  posteriorly  it  becomes  more  narrow.     In  the  vicinity 

Fig.  6. 


The  In-ferior  Maxillary  Boxe— External  Surface  of  the  Right  Side. 

M,  mental  process :  /,  incisive  fossa ;  F,  mental  foramen ;  L,  external  oblique  line ;  G,  groove 
for  facial  artery ;  A,  anterior  or  coronoid  process ;  P,  posterior  or  condyloid  process. 

of  the  rami  this  border  exhil^its  a  shaUoiv  groove,  in  which  the 
facial  artery  is  located. 

The  internal  surface  of  the  body  is  markedly  concave  from 
the  median  line  to  the  ramus,  and  slightly  convex  from  above 
downward.  (See  Fig.  7.)  In  the  central  line  we  observe  four 
tubercles,  two  above  and  two  below,  the  genial  fuhercles,  which 
vary  greatly  in  size  and  arrangement  in  different  individuals. 
Laterally  to  the  tubercles  we  notice  a  shallow  depression,  the 
sublingual  fossa,  in  which  the  sublingual  gland  rests.     Posterior 


THE    INFERIOR    MAXILLARY    BONE. 


11 


to  this  depression  is  the  beginning  of  the  internal  oblique  line 
or  rnylo-hijoid  ridge,  which  becomes  more  distinct  as  it  passes  up- 
ward and  backward.  The  portion  above  this  line  is  smooth 
and  covered  by  the  oral  mucous  membrane,  whereas  the  portion 
below  shows  a  shallow  depression,  the  submcLrillory  fossa,  corre- 
sponding to  the  site  of  the  submaxillary  gland. 

The  perpendicular  projections,  or  rami,  have  a  more  or  less 
quadrilateral  shape,  each  ramus  presenting  two  surfaces,  four 
borders,  and  two  offshoots.  The  external  surface  is  ridged,  and 
serves  for  the  attachment  of  the  masseter  muscle.     The  internal 


Fig.   7. 


The  Inferior  Maxillary  Boxe— Isterxal  Surface  of  the  Right  Side. 

0.  genial  tubercles ;  M,  mylo-hyoid  ridge :    0,  opening  of  the  inferior  dental  canal ;   H, 
mylo-hyoid  groove  ;  A,  anterior  or  coronoid  process ;  P,  posterior  or  condyloid  process. 


surface  is  pierced  about  its  center  by  an  oblique  aperture,  the 
opening  of  the  inferior  dental  canal.  Anteriorly  this  aperture  is 
surmounted  by  a  ridge  terminating  in  a  sharp  spine,  which  at  its 
lower  part  shows  a  notch  leading  to  the  mylo-hyoid  groove,  for  the 
mylo-hyoid  vessels  and  nerve.  The  lower  border  of  the  ramus 
exhibits  a  large  rough  surface  for  the  attachment  of  the  internal 
pterygoid  muscles. 

The  inferior  dental  canal  takes  an  oblique  course  downward 
and  forward  in  the  ramus,  and  a  horizontal  one  in  the  body. 
This  canal  is  located  underneath  the  sockets  of  the  teeth,  with 


12  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

which  it  communicates  by  small  openings.  At  a  point  about 
level  with  the  first  bicuspid  tooth  it  ends  in  the  mental  foramen. 
In  the  posterior  two-thirds  of  the  bone  the  inferior  dental  canal 
runs  near  the  internal  surface,  while  in  the  anterior  third  it  is 
near  the  external  surface.  This  canal  holds  the  inferior  dental 
vessels  and  nerve,  from  which  small  branches  pass  to  the  apices 
of  the  roots  of  the  teeth  through  the  small  openings  at  the  bases 
of  the  alveoli  referred  to  above. 

The  upper  border  of  the  ramus  is  thin,  and  shows  two  pro- 
cesses, the  anterior  or  coronoid,  and  the  posterior  or  condyloid. 
Situated  between  these  processes  is  a  deep  depression,  the  sig- 
moid notch.  The  coronoid  process  is  a  thin  piece  of  bone  serving 
mainly  for  the  attachment  of  the  temporal  muscle,  and — at  its 
outer  surface — for  the  attachment  of  the  masseter  muscle. 
The  condyloid  process  is  more  massive  than  the  coronoid,  and 
terminates  in  the  condyle,  which  is  covered  with  hyaline  carti- 
lage. The  condyle,  placed  upon  a  constricted  portion  of  the 
neck,  is  of  an  oblong  shape.  Its  long  axis  is  set  obliquely  upon 
the  neck,  the  outer  extremity  being  higher  and  directed  more 
forward  than  the  inner.  Its  surface  is  convex  both  antero-pos- 
teriorly  and  from  side  to  side. 

The  lower  border  of  the  ramus  is  thick  and  continuous  with 
the  body  of  the  bone.  At  the  angle  of  the  jaw  it  is  marked  by 
oblique  ridges  on  each  side,  for  the  attachment  of  the  masseter 
and  internal  pterygoid  muscles. 

The  posterior  border  of  the  ramus  is  covered  by  the  parotid 
gland. 

Development  and  Involution. — The  lower  jaw,  one  of  the 
first-formed  bones  of  the  embryo,  is  developed  principally  from 
a  hyaline  cartilage,  which,  in  honor  to  its  discoverer,  is  termed 
Meckel's  cartilage.  The  formation  of  osseous  tissue  begins  about 
the  sixth  week  of  intra-uterine  life.     (See  Fig.  8.) 

Meckel's  cartilage,  invested  by  perichondrium, — which  at  this 
stage  is  not  as  yet  fibrous,  but  made  up  of  spindle-shaped  proto- 
plasmic bodies, — forms  a  ledge,  from  and  around  which  ossifica- 
tion takes  place.  The  perichondrium  plays  as  great  a  part  in 
the  production  of  bone-tissue  as  the  cartilage  itself.  The  first 
step  toward  the  development  of  bone  is  the  calcification  of  the 
basis-substance  around  the  cartilage-corpuscles.  Il^ext  a  reap- 
pearance of  protoplasm  takes  place  in  the  non-calcified  portion 
of  the  basis-substance,  whereby  the  entire  territory  of  the  car- 


THE    INFERIOR    MAXILLARY    BONE. 


13 


tilage-corpiiscle  is  rendered  graiiiilar.  An  increase  in  the  size 
of  the  granules  results  in  an  augmentation  of  the  nuclei,  and  at 
last  the  entire  cartilage-corpuscle  is  transformed  into  a  cluster 
of  medullary  or  embryonal  corpuscles,  which  furnish  the  mate- 
rial for  bone-production.     A  preliminary  stage  of  ossification  is 


Fig.  8. 


FiEST  Formed  Teabecul.e  of  Bone,  in  Lower  Jaw  of  Hcmax  Ejibryo,   Six 

Weeks  Old. 

//,  hyaline,  or  primordial,  or  Meckel's  cartilage  ;  N,  non-calcified  basis-substance  around  the 
territories  of  hyaline  cartilage  ;  L,  calcified  basis-substance  of  territories  of  cartilage-corpuscles; 
B.  cartilage  broken  up  to  embryonal  or  medullary  corpuscles;  ij,  coarsely  granular  cartilage- 
corpuscles:  C,  calcified  embryonal  corpuscles;  T,  trabeoulfe  of  bone-tissue  with  territories; 
M,  M,  M,  myxomatous  or  medullary  connective  tissue.    Magnified  200  diameters. 


a  deposition  of  lime-salts  in  a  number  of  embryonal  corpuscles, 
derived  either  from  the  hyaline  cartilage  or  the  perichondrium. 
By  the  coalescence  of  a  number  of  such  bodies  territories  of 
globular  shape  are  formed,  the  center  of  the  globules  being 


14 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


occupied  by  bone-corpnscles,  while  the  peripheral  portion  is 
transformed  into  glue-vielding  basis-substance,  saturated  with 
lime-salts.  This  change  does  not  alter  the  structure  of  the  pro- 
toplasm. The  trabecule!?  of  bone  are  originally  small  and  irreg- 
ular;  later  they  unite  into  cancellous  tissue,  inclosing  medullary 
spaces  tilled  with  protoplasmic  bodies  and  carrying  blood-vessels. 
In  the  second  half  of  the  third  month  the 
Fig.  9.  maxilla  is  as  yet  a  minute  ledge  of  bone,  but 

-rrj^^"^'^^  with  indications  of  future  sockets,  and  of  the 

coronoid  and  condyloid  processes.-    (See  Fig.  9.) 
In  the  first  half  of  the  seventh  month  the 


Infekior  Maxilla 
OF  AN  Embryo ix  the 
Second  Halk  of  the 
Third  Month. 


future  sockets  of  the  teeth  are  wide  and  irreg- 


ular excavations.  Both  the  coronoid  and 
condyloid  processes  are  plainly  seen,  the  latter  being  almost 
horizontal.  The  mental  foramen  is  already  established.  (See 
Fig.  10.) 

At  the  time  of  birth  the  lower  jaw  is  made  up  of  tw^o  pieces, 
articulating  in  the  center  line.  The  upper  border  of  these  pieces 
is  grooved,  without  being  subdivided  into  sockets.  The  cortical 
portion  is  imperfect  and  pierced  by  numerous  medullary  spaces, 
especially  near  the  central  symphysis  and  in  the  region  of  the 
rami.  The  coronoid  is  more  advanced  in  size  than  the  condyloid, 
which  latter  retains  a  nearly  horizontal  position.     (See  Fig.  11.) 

In  the  sixth  year  ot"  life  the  inferior  maxillarj'  bone  has  at- 
tained a  considerable  size,  and  the  condyloid  process  is  inserted 
at  an  obtuse  amile.     Of  the  teeth  we  observe  on  either  side  of 


Fig.  10. 


Fig.  11. 


Inferior  Maxilla  of  a  Fcetus  in 
THE  First  Half  of  the  Seventh 
Month. 


Inferior  Maxilla  at  the  Time  of  Birth. 


the  jaw  the  two  temporary  incisors,  the  cuspid,  and  three 
molars, — two  temporary  and  one  (the  sixth-year)  permanent. 
(See  Fig.  12.)  In  the  adult  the  condyloid  process  is- conspicuous 
by  its  almost  rectangular  junction  with  the  ramus,  whereas  with 
advancing  age  this  process  appears  inserted  again  at  an  obtuse 
angle. 

In  old  age  the  lower  jaw  gradually  returns  to  its  embryonal 


THE  i>;ferior  maxillary  bone. 


15 


shape.  (See  Fig.  13.)  After  the  teeth  are  lost,  the  sockets  become 
obliterated,  and  are  replaced  bv  small  pits  and  grooves,  the  points 
at  which  the  conversion  of  the  bone  into  medullary  tissue  begins. 
The  mental  foramen  is  now  seen  to  be  near  the  previous  alveolar 
surface,  and  to  be  considerably  widened.     The  body,  as  well  as 

Fro.   12. 


Inferior  Maxilla  of  a  Boy  Six  Years  Old. 
Fig.  13. 


Ikferioe  Maxilla  in  Senile  Age. 

the  ramus,  is  reduced  to  a  thin  ledge  of  bone,  mostly  smooth  at 
the  surface.  The  laws  of  development,  as  well  as  of  senile 
involution,  are  not  as  yet  fully  understood.  It  is  certain,  how- 
ever, that  all  changes  take  place  by  juxtaposition,  and  not  by 
interstitial  growth.  All  phenomena  become  intelligible,  if  we 
admit  the  fact  that  not  only  are  the  bone-corpuscles  endowed 
M^ith  properties  of  life,  but  so  also  is  the  basis-substance,  and 
thus  both  are  enabled  to  be  reconverted  into  protoplasm,  and 
ao;ain  to  scive  rise  to  connective  tissue. 


16 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


CHAPTER   III. 


THE   TEETH. 


The  tooth,  macroscopically  considered,  consists  of  a  crown,  a 
neck,  and  a  root.  Tlie  crown  of  a  tooth  is  that  portion  which 
is  covered  with  enamel,  and,  when  the  tooth  is  fully  erupted,  is 
exposed  above  the  margin  of  the  gum.  The  neck  is  the  part 
that  is  covered  by  the  gum.  It  begins  at  the  border  of  the 
enamel  and  extends  to  the  alveolar  process.  The  root,  in  its 
normal  condition,  is  entirely  inclosed  by  the  alveolar  process. 


The  Right  Tekth  of  ax  Adult   Twexty-tato  Y'eaks  Old.    External  View.    Labial 

(Buccal)  Surfaces.* 


Between  the  neck  and  the  root  of  a  tooth  we  observe  no  distinct 
macroscopical  boundary,  but  for  descriptive  purposes  and  for 
practical  convenience  we  employ  differentiating  terms. 

The  dental  formula  that  represents  the  permanent  teeth  of  the 
human  mouth  is  noted  as  follows: 


(See  Figs.  14  and  15.) 


Ci;  B|;  M|  =  32 


-The  teeth  Xos.  9,  10,  11,  12,  13,  14,  15,  16,  17,  18,  19,  20,  21,  22,  23,  and  24, 
in  shape  correspond  with  their  fellows  of  the  opposite  side  of  the  dental  arch, 
except  that  the  general  shape  of  their  crowns  is  reversed,  and  it  has  therefore 
been  deemed  imnecessarv  to  illustrate  them. 


THE    TEETH. 


17 


Upon  examining  the  crown  of  a  tooth,  we  observe  on  it  five 
surfaces.  First,  the  outer  surface  in  regard  to  all  teeth,  called 
the  "  labial"  surface  of  the  front  teeth,  and  the  "  buccal"  surface 
of  the  bicuspids  and  molars.  Second,  the  inner  surface,  in  con- 
tact with  the  tongue,  and  therefore  called  "lingual."  Thirds 
the  " grinding-surfaces"  and  the  "cutting-edges,"  the  former 
name  being  applied  to  the  under  surfaces  of  the  upper  bicuspids 
and  molars  and  the  corresponding  grinding-surfaces  of  the  lower 
bicuspids  and  molars,  while  the  second  term  is  given  to  the 
similarly  opposed  edges  of  the  front  teeth.  The  two  surfaces  of 
each  tooth  still  to  be  named  are  those  that  are  in  contact  with  the 
neighboring  teeth.     The  surface  of  each  tooth  directed  toward 


25        26        27*'        28  29 


The  Right  Teeth  op  an  Adult  Twenty-two  Years  Old.    Internal  View.    Lingual 

Surface. 


the  center  of  the  jaw  is  called  "  mesial";  that  toward  the  poster- 
ior portion  of  the  dental  arch  is  known  as  the  "  distal."  There 
are  four  incisors  in  the  upper  and  four  in  the  lower  jaw.  The 
two  middle  ones  are  termed  "  central  incisors"  ;  the  two  outer, 
"  laterals."  Their  cutting-edges,  when  the  teeth  are  erupted, 
usually  exhibit  three  protuberances,  which,  in  use,  soon  become 
smooth  through  wear.  The  upper  incisors,  especially  the 
centrals,  are  much  larger  than  the  lower  ones,  and  in  normal 
articulation  overlap  the  latter.  The  upper  incisors  are  inclined 
toward  the  median  line,  rendering  the  mesial  surfaces  somewhat 
longer  than  their  corresponding  distal  surfaces.  The  incisors 
are  wedge-shaped,  thinning  from  the  base  at  the  gum  toward 

3 


18  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

the  cutting-edges.  These  edges,  in  adult  teeth,  viewed  anteriorly, 
represent  a  straight  line.  The  general  shape  of  an  incisor  thus 
anteriorly  seen  is,  approximately,  that  of  a  square,  though  it 
narrows  toward  the  neck.  The  mesial  angle  of  the  cutting-edge 
always  inclines  more  than  the  distal.  From  this  tapering  of  the 
crowns  of  the  teeth  toward  their  necks  result  more  or  less  V- 
shaped  spaces,  which  vary  in  diiferent  mouths.  In  some 
instances  we  meet  with  teeth  of  which  the  crowns  are  almost 
square,  in  which  case  the  intervening  spaces  at  the  necks  are 
quite  small ;  while  between  teeth  which  exhibit  broad  cutting- 
edges  and  narrow  necks  we  observe  large  Y-shaped  spaces. 

The  upper  incisors  usually  have  single  roots,  which  are  more 
or  less  conical  toward  the  apices. 

The  labial  surfaces  of  the  upper  incisors,  especially  in  young 
subjects,  are  mostly  marked  by  slight  longitudinal  depressions 
and  elevations,  which,  through  wear,  gradually  disappear  with 
advancing  age.  In  adults  the  labial  surfaces  are  more  or  less 
smooth  and  slightly  convex.  In  some  instances  we  meet  with 
transverse  furrows  or  pits  in  these  surfaces,  which,  however, 
must  be  regarded  as  abnormalities.  The  enamel  at  the  gingival 
border  of  the  labial  surface  terminates  in  a  curved,  somewhat 
elevated  ridge.  The  lingual  surfaces  are  irregularly  concave. 
The  periphery  is  bounded  by  a  more  or  less  prominent  ridge  of 
enamel,  which,  toward  the  margin  of  the  gum,  forms  what  is 
known  as  the  hasaJ  ridge  or  cim/ul'i/n.  This  basal  ridge  is 
frequently  found  to  be  divided  by  a  deep  groove  or  pit,  which, 
in  the  majority  of  such  cases,  soon  becomes  the  seat  of  caries. 
The  boundary  line  of  the  enamel  on  the  lingual  surface  is  curved 
similarly  to  that  of  the  labial  surface.  These  ridges,  as  they  turn 
into  the  mesial  and  distal  surfaces  of  the  incisors,  take  a  down- 
ward course,  following  the  festoons  of  the  gum,  and  meet  with 
the  enamel  ridge  of  the  labial  surface,  producing  a  Y-shaped 
appearance  in  both  the  mesial  and  distal  surfaces  of  the  teeth. 

The  a2:)2)er  central  incisors  (Kos.  8  and  9)  occupy  the  center  in 
the  dental  arch,  being  the  broadest  of  the  incisor  teeth.  Their 
roots  are  almost  cylindrical,  and  gradually  taper  from  the  neck 
toward  the  apex. 

The  upper  lateral  incisors  (Xos.  7  and  10)  are  smaller  than  the 
centrals.  The  mesial  angle  of  their  cutting-edge  usually  over- 
hangs more  than  that  of  the  central  incisors,  in  consequence  of 
which  their  distal   angles  appear  more  rounded.     Their  roots 


THE    TEETH.         •  19 

are  compressed  laterally,  and  taper  frora  crown  to  apex,  corre- 
sponding in  length  to  those  of  the  central  incisors. 

The  lower  central  incisors  (Nos.  24  and  25)  are  the  smallest  teeth 
in  the  dental  arch.  They  are  even  smaller  than  the  upper  lat- 
erals. Their  general  outline  is  the  same  as  that  of  the  upper 
laterals,  but  the  angle  of  their  mesial  surfaces  is  much  less  over- 
hanging. Their  lingual  surface  is  usually  smooth  and  but 
slightly  concave.  The  roots  of  these  teeth  are  more  compressed 
laterally  than  those  of  the  upper  laterals. 

The  lower  lateral  incisors  (iSTos.  23  and  26)  are  somewhat  wider 
than  the  centrals  of  the  lower  jaw,  yet  in  every  other  respect 
their  appearance  is  the  same  as  that  of  the  central  incisors, 
although  their  roots  are  a  little  longer  and  heavier. 

The  upper  canines,  eye-teeth,  or  cuspids  (Nos.  6  and  11)  occupy  a 
prominent  position  on  either  side  of  the  incisor  teeth.  They 
form  the  corners  of  the  dental  arch,  and  are  in  every  respect 
more  stoutly  built  than  the  incisors.  The  crown  terminates  in 
a  more  or  less  blunt  point,  from  either  side  of  which  a  rounded 
cutting-edge  slopes  away  and  becomes  continuous  with  the 
mesial  or  distal  surface.  The  cuttino^-edsre  of  the  mesial  surface 
is  somewhat  shorter  than  that  of  the  distal  surface.  By  this 
diiference  in  the  length  of  the  cutting-edges  we  are  enabled  to 
distinguish  the  teeth  belonging  to  the  right  from  those  of  the 
left  side  of  the  mouth.  Upon  the  labial  surface  of  an  upper 
cuspid  tooth  we  observe  a  somewhat  prominent  ridge,  which 
extends  from  the  summit  of  the  cusp  to  the  neck.  This  ridge 
renders  the  surface  more  convex  than  the  corresponding  labial 
surface  of  an  incisor  tooth.  In  the  median  line  of  the  lingual 
surface  of  an  upper  cuspid  we  also  observe  a  ridge,  the  direction 
of  which  is  identical  wdth  that  of  the  labial  surface.  In  some 
instances,  where  this  ridge  joins  the  cingulum,  it  develops  into 
a  regular  small  cusp,  which  in  shape  is  not  unlike  that  of  a 
lower  first  bicuspid  tooth.  The  mesial  and  distal  surfaces  are 
of  a  triangular  form,  similar  to  those  of  the  incisor  teeth ;  but 
their  base  is  much  broader.  The  roots  of  the  upper  cuspid 
teeth  are  much  stouter  and  longer  than  those  of  the  incisors, 
and  are  usually  somewhat  compressed  laterally.  The  position 
of  these  roots  in  the  mouth  can  easily  be  determined,  since  they 
are  marked  by  a  prominent  ridge  upon  the  external  surface  of 
the  maxillary  bones,  the  canine  eminences. 

The  shape  of  the  lower  cuspids  (il^os.  22  and  27)  does  not  dififer 


20  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

much  from  that  of  the  upper  ones,- although  they  are  smaller -in 
ever}'  respect.  The  ridges  upon  their  lingual  surfaces  are  not  so 
prominently  developed,  and  their  roots  are  shorter. 

The  premolars  or  bicuspids,  eight  in  number  (jSTos.  4,  5,  12, 
13,  20,  21,  28,  and  29),  are  arranged  in  pairs,  both  in  the  upper 
and  lower  jaws,  posterior  to  the  cuspids.  Their  crowns  are 
quadrilateral;  but  the  buccal  portion  of  the  crown  is  larger 
than  its  lingual  half,  as  is  especially  noticeable  in  the  first  bi- 
cuspids. The  shape  of  the  buccal  surface  of  a  bicuspid  is  similar 
to  that  of  the  cuspid  of  the  same  side  of  the  mouth ;  the  ridge, 
however,  extending  from  the  summit  of  the  cusp  to  the  margin 
of  the  gum,  is  not  so  strongly  marked.  The  grinding-surface 
of  a  bicuspid,  as  the  name  implies,  exhibits  two  cusps,  of  which 
the  buccal  is  the  largest.  These  cusps  are  separated  from  each 
other  by  a  furrow  which,  in  some  teeth,  is  quite  deep,  and  often 
becomes  the  seat  of  caries.  The  mesial  and  distal  portions  of 
this  furrow  are  bounded  by  a  small  ridge  of  enamel,  continuous 
with  the  sloping  lingual  and  buccal  edges  of  the  cusps.  The 
cutting-edges  are  similar  to  those  of  the  cuspid  of  the  same  side 
of  the  dental  arch. 

The  upper  bicuspids  (Nos.  4,  5,  12,  and  13)  are  somewhat 
larger  than  those  of  the  lower  jaw,  and  their  lingual  cusps  are 
more  developed.  The  lingual  portion  of  the  crown  of  the  fi.rst 
upper  bicuspid  is  narrower  antero-posteriorly  than  its  buccal 
half.  The  shape  of  the  crown  of  the  second  bicuspid  is  more 
nearly  square,  and  the  entire  tooth  a  little  stouter  than  the  first. 
The  root  of  the  first  upper  bicuspid  always  is  much  compressed 
laterally,  and,  as  a  rule,  contains  two  pulp-canals.  Sometimes- 
its  root  is  bifurcated,  while  the  upper  second  bicuspid  seldom 
has  more  than  one  root,  or  one  pulp-canal. 

The  lower  bicuspids  (ISTos.  20,  21,  28,  and  29)  are  smaller  than 
those  of  the  upper  jaw.  Their  crowns  are  roundish  and  some- 
what bent  inward.  Their  roots  are  conical.  The  first  lower 
bicuspid  is  the  smallest  of  the  bicuspids.  Its  outer  cusp  is  much 
higher  than  the  inner  one,  which  is  but  slightly  developed. 
From  the  buccal  to  the  lingual  cusp  extends  a  small  ridge,  on 
either  side  of  which  is  sunken  a  little  pit,  a  favorite  seat  of 
decay.  The  second  lower  bicuspid  is  larger  than  the  first,  and 
its  lingual  cusp  is  more  developed  than  that  of  the  first  lower 
bicuspid. 

If  we  compare  the  incisors  with  the  cuspids  and  bicuspids, 


THE    TEETH.  21 

we  find  that  there  exists  a  typical  analogy  between  their  shapes, 
which,  however,  is  not  the  case  if  we  compare  the  incisors  with 
the  molars. 

The  molar  teeth  QSo^.  1,  2,  3,  14, 15,  16,  17,  18,  19,  30,  31,  and 
32)  are  the  largest  in  the  mouth,  and  occupy  the  posterior  por- 
tion of  the  dental  arch.  jS^orrnally  there  are  six  molars  in  each 
jaw,  three  on  either  side.  The  third  molar,  also  called  wisdom- 
tooth,  is,  however,  frequently  missing,  and  in  a  crowded  dental 
arch  may  remain  unerupted.  This  deficiency  is,  in  some  fami- 
lies, characteristic  and  hereditary.  The  crowns  of  the  first 
molars  are  larger  than  those  of  the  second,  and,  in  turn,  the 
crowns  of  the  second  are  larger  than  those  of  the  third.  The 
grinding-surface  of  a  molar  is  of  a  more  or  less  square  shape, 
with  rounded  angles,  and  is  made  up  of  four  or  five  cusps. 
The  mesio-buccal  cusp  of  a  molar  usually  is  a  little  larger  than 
the  others,  which  fact  enables  us  to  determine  to  which  side  of 
the  mouth  the  tooth  belongs. 

The  crowns  of  the  upper  molars  (Nos.  1,  2,  3,  14,  15,  and  16), 
especially  the  first  and  second,  usually  exhibit  a  cusp  upon  each 
of  their  angles,  of  which  the  mesio-lingual  is  the  largest.  The 
mesio-buccal  cusp  is  connected  with  the  mesio-lingual  one  by  a 
ridge  which  runs  along  the  mesial  border  of  the  grinding-sur- 
face. Sometimes  we  observe  upon  the  mesio-lingual  border  of 
the  crown  of  the  first  and  second  upper  molars  a  small  extra 
cusp,  separated  from  the  large  mesio-lingual  by  a  deep  furrow. 

The  furrows  separating  the  cusps  run  over  the  buccal  and 
lingual  borders  of  the  grinding-surface.  The  furrow  upon  the 
lingual  surface  usufilly  terminates  in  a  more  or  less  deep  pit, 
which,  together  with  the  above-described  fissures  of  the  grind- 
ing-surface, famishes  a  favorable  locality  for  the  development 
of  caries.  The  roots  of  each  upper  molar  are  usually  three  in 
number, — two  buccal,  much  compressed  antero-posteriorly,  and 
one  lingual  or  palatal.  The  lingual  root  is  the  stoutest  of  the 
three,  conical  in  form,  diverging  from  the  axis  of  the  crow^n 
toward  the  palate,  and  often  slightly  curved  in  the  direction  of 
the  buccal  roots.  The  crown,  as  well  as  the  roots  of  the  upper 
third  molar,  or  wisdom-tooth,  is  liable  to  great  variations.  In 
the  majority  of  instances  we  find  the  crown  of  a  third  upper 
molar  much  smaller  and  shorter  than  that  of  the  first  or  second 
molar.  This  molar  sometimes  has  only  one  straight,  short  root, 
but  in  some  instances  it  is   supplied   with  three, — the  typical 


22  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

number, — four,  or  even  live.  Occasionally  the  roots  of  the 
wisdom-teeth  are  normally  developed,  like  those  of  the  first  and 
second  molars;  mostly,  however,  they  are  but  rudimentary  and 
more  or  less  compressed,  or  even  conglomerated  into  one  root. 

The  grinding-surfaces  of  the  lower  molar  ieefh  (Nos.  17, 18,  19, 
30,  31,  and  32)  usually  exhibit  five  cusps,  separated  from  one 
another  by  deep  farrows,  representing  a  regular  cross.  The 
posterior  arm  of  this  furrow,  as  a  rule,  bifurcates  and  winds 
around  the  fifth  cusp.  The  lingual  and  buccal  portions  of  the 
farrow  extend  into  the  lingual  and  buccal  surfaces  of  the  tooth. 
Especially  upon  the  buccal  surface  of  the  lower  molars  the  fur- 
row is  quite  deep,  terminating  in  a  pit,  which,  like  that  of  the 
upper  molars,  frequently  decays.  The  cusps  are  placed,  one  at 
each  of  the  four  angles  of  the  grinding-surface,  while  the  fifth 
cusp,  the  smallest,  is  situated  upon  the  posterior  border  of  this 
surface.  The  lower  molars,  with  the  exception  of  the  third, 
usually  are  implanted  with  two  roots,  which  in  the  jaw  occupy 
an  antero-posterior  position  and  are  much  compressed  in  the 
antero-posterior  direction.  Occasionally  we  observe  that  the 
mesial  root  of  the  first  lower  molar  is  bifurcated. 

The  Temporary,  Deciduous,  or  Milk  Teeth. — In  the  mouth  of 
an  infant,  about  the  sixth  month  after  its  birth,  we  observe  the 
appearance  of  the  first  teeth,  which  belong  to  the  so-called 
"  ternporari/"  or  "  deciduous"  set.  The  complete  denture  of  a 
child  is  comprised  of  twenty  teeth,  which  are  noted  as  follows : 
T  II;  TCI;  T  M  #  =  20. 

(See  Fig.  16.) 

The  temporary  incisor  and  cuspid  teeth  are  similar  to  those 
of  the  permanent  set,  though  much  smaller.  The  bicuspids  are 
absent.  Their  arrangement  in  the  dental  arch  is  the  same  as 
that  of  their  respective  successors ;  but  the  temporary  molars 
occupy  on  either  side  of  the  cuspids  the  places  which  in  the 
permanent  set  are  filled  by  the  bicuspids. 

The  crowns  of  the  temporary  teeth  are  large  in  proportion  to 
their  necks  and  roots,  the  enamel  terminating  in  a  rather  thick 
ridge,  which  is  a  characteristic  feature  of  all  the  temporary 
teeth. 

In  the  illastration  I  have  adopted  the  numbering  of  the  tem- 
porary^ teeth  from  one  to  twenty,  adding  a  T,  to  distinguish 
them  from  the  permanent  teeth. 

No.  1  T,  the  right  up-per  second  molar,  is  the  largest  of  the  upper 


THE    TEETH. 


23 


molars.  In  shape  its  crou^ii  resembles  that  of  the  first  perma- 
nent upper  molar ;  but  its  roots,  besides  being  smaller,  diverge 
much  more  from  the  center  than  do  those  of  the  permanent 
teeth.  The  grinding-surface  is  surmounted  usually  by  four, 
sometimes  by  five,  cusps,  arranged  in  the  same  manner  as  those 
of  the  first  permanent  upper  molar. 

JVo.  2  T,  the  right  upper  frst  molar,  is  considerabh'  smaller  than 
Xo.  1  T.  Upon  the  grinding-surface  we  usually  find  but  two 
cusps,  one  upon  the  buccal,  the  other  upon  the  lingual  aspect. 
They  are  divided  by  a  deep  furrow.  There  are  three  roots, 
which  in  shape  and  arrangement  are  similar  to  those  of  molar 
!N"o.  1  T,  but  somewhat  smaller. 


20.T.  I9.T.  I8.T.  I7T.  I6.T. 

The  Right  Temporary  or  DECiDuors  Teeth. 


No.  3  T,  (he  right  upper  cuspid,  while  in  its  principal  character- 
istics similar  to  its  successor,  in  proportion  is  much  smaller  and 
shorter  than  the  permanent  cuspid.  It  is  implanted  by  a  single, 
almost  cylindrical  root. 

Nos.  4-  Tando  T,  the  right  upper  lateral  and  central  incisors,  excep)t 
in  being  smaller  than  their  successors,  are  in  their  general  out- 
lines much  like  the  latter,  only  their  crowns  are  shorter  in  pro- 
portion to  those  of  the  corresponding  permanent  teeth.  They 
invariably  have  but  one  root,  of  a  conical  shape. 

Temporary  teeth  Nos.  6,  7,  8,  9,  and  10  of  the  upper  jaw,  as  well 
as  Nos.  11,  12,  13,  llf,  and  15  of  the  lower  jaw,  are  identical  in 
character  with  their  fellows  of  the  opposite  side,  with  the  excep- 
tion that  the  forms  of  their  crowns  are  reversed. 

Nos.  16  T  and  17  T,  the  right  lower  central  and  lateral  incisors. 
The  principal  difference  between  these  teeth  and  their  permanent 


24  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

successors  is  that  the  former  are  much  smaller,  have  a  more  or 
less  conical  root,  and  their  enamel  terminates  at  the  neck  in  a 
thick  ridge,  which  is  common  to  all  temporary  teeth. 

No.  18  T^  the  right  lower  cuspid.  Its  crown  usually  is  some- 
what longer  than  that  of  the  upper  temporary  cuspid,  but  not 
so  stout;    while  its  root,  like  that  of  No.  3  T,  is  nearly  conical. 

Xo.  19  T,  the  right  lower  first  molar.  Its  crown  is  smaller  than 
that  of  ]^o.  20  T.  Upon  its  grinding-surface  we  commonly  lind 
four  small  cusps.  It  is  implanted  by  two  roots,  flattened  antero- 
posteriorly,  and  diverging  considerably  from  the  center. 

i\o.  20  T,  the  right  lower  second  mohu\  is  the  largest  of  all  the 
temporary  molars.  Its  grinding-surface  is  surmounted  by  four, 
sometimes  five,  cusps,  arranged  in  the  same  manner  as  those  of 
the  first  permanent  lower  molar.  It  has  two  roots,  which  in 
shape  and  position  are  similar  to  those  of  the  first  temporary 
molar,  though  much  larger,  and  in  some  instances  almost  as 
stout  as  those  of  the  permanent  lower  molars. 


CHAPTEE   lY. 

INDIVIDUAL   CHARACTERISTICS   OF  THE   TEETH. 

Disting-uishing  Features  between  the  Temporary  and  the 
Permanent  Teeth. — The  main  peculiarity  of  temporary  teeth 
is  that  they  are  much  smaller  than  the  permanent  ones.  The 
enamel  of  the  temporary  teeth  terminates  at  the  neck  in  a  rather 
thick  ridge,  whereby  the  necks  of  these  teeth  appear  much 
smaller  in  proportion  than  those  of  the  permanent  teeth.  The 
temporary  incisors  oflier  another  marked  characteristic  in  their 
smooth  cutting-edges,  while  those  of  permanent  teeth,  in  the 
juvenile  condition,  are  each  of  them  surmounted  by  three  small 
protuberances. 

The  temporary  cuspids  are  much  shorter,  narrower,  and  have 
a  less  pointed  cusp  than  their  permanent  successors. 

The  crown  of  a  first  temporary  molar  is  so  typical  that  it 
scarcely  will  be  mistaken  for  a  permanent  tooth.  Its  roots  are 
much  smaller  than  those  of  a  permanent  molar,  and  diverge 
considerably  from  the  center. 

The  second  temporary  molars,  on  the  contrary,  while  in  the 
jaws,  may  sometimes  be  confounded  with  a  permanent  sixth-year 


INDIVIDUAL    CHARACTERISTICS    OF    THE    TEETH.  25 

molar ;  but  as  this  always  is  the  fifth  tooth  from  the  center,  its 
position  will  aid  us  in  making  the  distinction. 

Distinguishing  Peculiarities  between  the  Upper  and  Lower 
Permanent  Teeth. — The  principal  difference  existing  betw^een 
the  incisors  of  the  upper  and  those  of  the  lower  jaw  is  that  the 
crowns  of  the  former  are  much  broader  than  those  of  the  lower 
incisors.  While  the  crowns  of  the  latter  are  the  smallest  in  the 
mouth,  they  are,  at  the  same  time,  noticeably  compressed  laterally 
toward  their  necks. 

The  upper  cuspids,  or  eye-teeth,  are  the  stoutest  teeth  possess- 
insr  sino;le  roots,  much  lar2:er  than  the  lower  ones.  The 
cingulum  and  the  ridge  upon  the  lingual  surface  of  the  lower 
cuspids,  which  are  so  marked  in  the  upper,  are  but  little  devel- 
oped. 

The  main  difference  between  the  bicuspids  of  the  upper  and 
those  of  the  lower  jaw  is  that  the  crowns  and  roots  of  the  former 
are  somew^hat  compressed  antero-posteriorly,  w^iile  the  roots  and 
the  crowns  of  the  latter  are  nearly  cylindrical.  There  is  also  a 
difference  in  their  lingual  cusps,  which  in  the  upper  bicuspids  are 
long,  in  the  lower  short,  sometimes  merely  rudimentary.  This 
last  is  especially  often  the  case  with  the  first  lower  bicuspid. 

To  discriminate  between  the  first  and  second  molars  of  the 
upper  and  lower  jaws,  it  is  only  necessary  to  notice  the  number 
of  their  roots,  since  the  former  usually  exhibit  three,  the  latter 
mostly  but  two.  Another  peculiarity  of  the  upper  molars  is 
the  arrangement  of  the  furrow  upon  the  grinding-surface,  which 
somewhat  resembles  the  letter  H,  w^hile  the  fissure  of  the  lower 
molars  represents  a  cross.  The  upper  and  low^er  wisdom-teeth, 
or  third  molars,  might  sometimes  be  confounded  with  each 
other,  because  both  are  often  implanted  with  a  single  conglom- 
erated root.  The  crown  of  a  lower  third  molar,  however,  even 
though  altered,  usually  represents  the  general  type  of  the  lower 
molars.  Upon  the  grinding-surface  of  a  lower  third  molar, 
therefore,  we  mostly  see  the  fissure  between  the  cusps  more  or 
less  in  the  form  of  a  cross. 

In  numbering  the  teeth,  the  writer  has  adopted  the  system 
employed  in  dental  registers  and  examination  tables.  (See  Figs. 
14  and  15.) 

JSfo.  1.  Right  upper  third  molar,  or  wisdom-tooth.  This  is  the 
smallest  of  the  three  molars.  The  crown  usually  exhibits  but 
three  cusps,  one  upon  the  lingual  and  two  upon  the  buccal  aspect. 


26  THE    ANATOMY    AND    PATHOLOOtY    OF    THE    TEETH. 

The  mesial  cusp  is  the  largest  of  the  three.  Usually  the  third 
molar  has  one  root,  sometimes  it  has  two ;  in  well-developed 
teeth  three  roots  may  be  present.  In  the  last  case  the  grinding- 
aurface  is  surmounted  by  four  cusps,  similar  in  arrangement  to 
those  of  the  other  molars. 

No.  3.  JRight  upper  second  molar.  This  is  a  trifle  larger  than 
jSTo.  1,  but  smaller  than  Eo.  3.  Its  cusps  and  roots  are  similar 
to  those  of  jSTo.  3,  though  its  crown  is  more  rounded.  Its  mesio- 
buccal  cusp  is  larger  than  the  distal  one,  and  the  tooth,  as  a  rule, 
is  possessed  of  three  distinct  roots. 

No.  3.  Bigld  upper  first  molar.  This  is  the  largest  of  the  upper 
molars.  Its  grinding-surface  is  of  a  rhomboidal  form,  the 
mesio-buccal  and  linguo-distal  angles  being  acute,  while  the 
disto -buccal  and  mesio-lingual  angles  are  obtuse.  Its  mesio- 
buccal  cusp  is  larger,  somewhat  lower,  and  more  rounded  than 
the  disto-buccal  one.     It  has  three  distinct  roots. 

No.  4-  mght  upper  second  bicuspid.  The  crown  of  this  tooth  is 
larger  than  that  of  any  other  bicuspid.  Its  lingual  cusp  is  slightly 
higher  and  better  developed  than  that  of  the  first  upper  bicuspid. 
The  mesial  portion  of  the  buccal  cusp  of  the  cutting-edge  is 
more  obliquely  inclined  than  the  distal.  The  root  is  usually 
single,  somewhat  compressed  laterally,  and  holds  but  one  pulp- 
canal. 

No.  5.  Right  upper  frrst  bicuspid.  This  tooth  is  a  trifle  smaller 
than  jSTo.  4,  especially  in  the  lingual  portion  of  its  crown.  The 
mesial  cutting-edge  of  the  buccal  cusp  is  directed  more  obliquely 
downward  than  that  of  the  distal.  The  root  is  usually  bifurcated, 
or  a  groove  runs  longitudinally  on  both  sides  of  the  root  in  the 
median  line,  indicative  of  two  pulp-canals,  which,  in  most 
instances,  are  present. 

No.  6.  The  right  upper  cuspid  has  a  single,  pointed  cusp,  of 
which  the  mesial  cutting-edge  is  directed  more  obliquely  down- 
ward than  the  distal.     It  has  one  long,  stout  root. 

No.  7.  Right  upper  lateral  incisor.  Its  crown  is  much  smaller 
than  that  of  a  central,  l^o.  8  or  9.  The  mesial  angle  of  the  cut- 
ting-edge is  more  overhanging  than  the  distal  one,  the  latter 
being  more  rounded.     It  has  a  single  compressed  root. 

No.  8.  Right  upper  centred  incisor.  The  crown,  like  that  of 
No.  9,  is  broad  and  square  in  its  labial  aspect.  The  mesial  angle 
of  the  cutting-edge  is  more  acute  than  the  distal,  which  is  some- 
what rounded.     It  has  a  single,  more  or  less  conical  root. 


INDIVIDUAL    CHARACTERISTICS    OF    THE    TEETH,  27 

The  teeth  Nos.  9,  10,  11,  12,  13,  II,.,  15,  and  16  are  identical  in 
shape  Avitli  the  corresponding  teeth  of  the  opposite  side  of  the 
dental  arch,  with  the  exception  that  the  general  shape  of  their 
crowns  is  reversed. 

No.  17.  Left  hirer  third  molar,  or  wisdom-tooth.  Its  crown  is 
somewhat  larger  than  that  of  the  npper  wisdom-tooth,  but  it  is 
always  the  smallest  of  the  lower  molars.  The  grinding-surface 
is  surmounted  by  four  or  five  cusps.  When  there  are  four,  the 
mesio-buccal  cusp  is  the  largest;  if,  however,  five  cusps  be 
present,  three  of  them  usually  are  upon  the  buccal  portion  of 
the  crown.  In  most  instances  it  has  one  or  two  more  or  less 
conical  roots,  curved  toward  the  posterior  portion  of  the  jaw. 

No.  18.  Left  lower  second  molar.  The  crown  is  nearly  scjuare, 
somewhat  larger  than  that  of  'No.  17,  but  not  quite  as  large  as 
that  of  No.  19.  The  grinding-surface  is  surmounted  by  four  or 
five  cusps,  of  which  two  are  situated  upon  the  lingual  and  two 
or  three  upon  the  buccal  portion  of  the  crown.  The  lingual 
cusps  are  always  a  little  higher,  but  more  pointed,  whereas 
the  buccal  cusps  are  broad  and  round.  By  the  shape  and  posi- 
tion of  these  cusps  we  are  enabled  to  determine  correctly  to 
which  side  of  the  dental  arch  the  molar  belongs.  This  molar 
usually  has  two  compressed  roots,  of  which  the  anterior  some- 
times holds  two  pulp-canals. 

No.  19.  Left  lower  first  molar.  Its  crown  is  almost  square. 
It  is  the  largest  of  the  lower  molars.  It  usually  has  five  cusps, 
of  which  two  are  situated  upon  the  lingual  and  three  upon  the 
buccal  portion  of  the  crown.  The  lingual  cusps  are  pointed, 
and  a  little  higher  than  the  three  buccal  ones,  the  latter  being 
rounder,  broader,  and  a  little  lower.  Of  the  buccal  cusps,  the 
mesial  is  usually  the  largest.  This  molar  generally  has  two,  but 
occasionally  three  roots,  two  anterior  and  one  posterior,  and  it 
almost  always  contains  one  posterior  and  two  anterior  pulp- 
canals. 

No.  20.  Left  hirer  second  bicuspid.  The  crown  is  larger  than 
that  of  No.  21,  its  lingual  cusp  a  little  lower  than  the  buccal. 
The  lingual  cusp  of  this  tooth  is  much  more  developed  than 
that  of  the  first  lower  bicuspid.  The  mesial  cutting-edge  of  the 
buccal  cusp  usually  is  more  oblicjuely  inclined  than  the  distal. 
The  root  is  mostly  single  and  conical. 

No.  21.  Left  lower  first  bicuspid.  The  crown  is  the  smallest 
of  any  of  the  bicuspid  teeth,  nearly  round  in  circumference, 


28  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

and  somewhat  bent  upon  the  root  toward  the  lingual  portion  of 
the  dental  arch.  The  lingual  cusp  is  very  small,  though  pointed, 
and  connected  with  the  buccal  cusp  by  a  ridge  of  enamel  which 
divides  the  grinding-surface  and  thereby  produces  two  deep 
pits.  The  mesial  cutting-edge  of  the  buccal  cusp  is  more  ob- 
liquely inclined  than  the  distal.  It  usually  has  a  single  conical 
root. 

Xo.  2'2.  Left  lower  cuspid.  The  crown  is  narrower,  but  some- 
times longer  than  that  of  an  upper  cuspid.  Its  lingual  surface 
is  almost  flat,  or  slightly  concave,  and  the  mesial  cutting-edge  is 
more  obliquely  inclined  than  the  distal.  Its  root  is  mostly 
single,  but  flattened. 

No.  23.  Left  lower  lateral  incdsor.  Its  crown  is  somewhat 
narrower  than  that  of  an  upper  lateral,  but  not  quite  so  narrow 
as  that  of  a  lower  central  incisor.  The  mesial  angle  of  the 
cutting-edge  usually  is  similar  to  that  of  the  distal.  The  root  is 
much  more  compressed  laterally  than  that  of  an  upper  lateral 
incisor. 

No.  24-.  Left  lower  central  incisor.  The  crown  is  narrower 
than  that  of  any  other  incisor  tooth,  being  much  compressed 
laterally  at  the  neck.  Its  root  is  similar  in  shape  to  that  of  a 
lower  lateral  incisor. 

The  teeth  Nos.  25,  26,  27,  28,  29,  30,  31,  and  32  are  identical 
in  shape  with  the  corresponding  teeth  of  the  opposite  side  of  the 
dental  arch,  with  the  exception  that  the  general  configuration 
of  the  crowns  is  reversed.  It  should  be  noted,  however,  that 
in  the  lower  laterals  and  central  incisors  both  angles  of  the 
cutting-edges  are  about  equal.  It  is  in  most  cases  impossible 
to  determine  to  which  side  of  the  dental  arch  a  lower  incisor 
belongs. 


CHAPTER  V. 

THE  PULP-CHAMBERS   OF   THE  TEETH. 

Every  tooth  incloses  a  central  cavity,  of  which  the  shape 
corresponds  to  that  of  the  exterior  of  the  tooth.  The  coronal 
portion  of  this  cavity  is  called  the  j^ulp-chamber,  while  the  portion 
in  the  root  of  the  tooth  is  known  as  the  root-canal.  It  is  of 
the  utmost  importance  to  the  dental  practitioner  to  be  thoroughly 


THE    PULP-CHAMBERS    OF    THE    TEETH, 


29 


familiar  with  the  forms  and  positions  of  the  pulp-chambers  of 
the  teeth,  since  a  proper  diagnosis  of  the  different  diseases  of 
the  dental  pulp  cannot  be  made  without  this  knowledge. 
Furthermore,  a  dentist  not  well  acquainted  with  the  anatomy  of 
the  pulp-chamber  is  liable  to  expose  a  pulp  unintentionally  dur- 
ing the  preparation  of  a  cavity  for  filling.  Within  every  cusp 
of  the  molars,  bicuspids,  and  cuspids  we  find  a  corresponding 
elevation  in  the  pulp-chamber,  while  in  the  crown  of  an  incisor 
the  cavity  is  somewhat  bifurcated. 

The  pulp-chambers,  as  well  as  the  root-canals,  are  filled  by 
myxomatous  connective  tissue,  interwoven  with  blood-vessels 
and  nerve-fibers,  termed  the  dental  pulp.     This  tissue  also  fills  the 

Fig.  17. 


Left   Teeth  ix  Linguo-Labial  and  Lisguo-Buccal  (Sagittal  turning  to  Frontal) 
Sections.    Reversed  to  the  Right  Side- 


protuberances  under  the  cusps  of  the  teeth,  these  portions  being 
called  the  horns  of  the  pulp.  The  latter  are  the  points  which, 
through  caries,  easily  become  exposed  and  diseased.  Although 
we  often  find  carious  cavities,  and,  consequently,  exposures  of 
the  pulp,  about  the  necks  of  the  teeth,  nevertheless  in  the 
majority  of  instances  the  dental  pulp  becomes  exjDOsed  at  one 
or  more  of  its  horns. 

G.  Carabelli"^  w^as  the  first  to  give  illustrations  of  the  pulp- 
chambers  of  the  teeth,  in  their  various  places,  but  without  cor- 
rect measurements.  He  published  elaborate  drawings  of  the 
pulp-chambers  of  both  the  temporary  and  the  i:>ermanent  teeth. 
Upon  comparing  the  charts  of  Carabelli,  however,  we  find  that 

*  Systematisches  Handbuch  der  Zahnheilkunde,  1844. 


30 


THE    ANATOMY    AND    PATHOLO(^^Y    OF    THE    TEETH. 


tlie  pnlp-eliaml)ers  of  tlie  teetli  tliere  depicted  do  not  correspond 
to  those  usually  met  Avitli  in  this  country,  which  difference  may 
perhaps  be  explained  by  the  fact  that  the  teeth  used  by  Cara- 
belli  were  of  a  different  type  from  those  of  our  generation. 

To  arrive  at  satisfactory  conclusions  in  the  study  of  the  pulp- 
chambers  of  the  human  teeth,  it  would  be  necessary  to  examine 
many  complete  sets  of  different  ages,  constitutions,  and  shapes. 
But  the  author  has  only  been  able  to  obtain  a  single  set  of  thirty- 
two  perfect  teeth,  which  were  imported  from  Tramond,  of  Ptiris. 
These  teeth  are  alleged  to  have  come  from  the  mouth  of  a  girl  about 
twenty-two  years  of  age.  Correct  drawings  were  made  of  them, 
as  represented  in  Figs.  14  and  15.     Afterward  the  sixteen  teeth  of 

Fig.  18. 


mi/    iir   III 

Right  Teeth  in  Lixgcal  axd  Buccal  (Feoxtal  tuexing  to  Sagittal]  Sections- 


the  left  side  were  ground  upon  a  corundum-wheel,  exposing  the 
mesial  or  frontal  aspects  of  the  pulp-chambers,  as  represented  in 
Fig.  17.  The  other  sixteen  teeth,  belonging  to  the  right  side  of 
the  dental  arch,  were  prepared  as  represented  in  Fig.  18,  exposing 
the  labial  aspect  (respectively  buccal  or  sagittal)  of  the  pulp-cham- 
bers. It  is  a  well-known  fact  that,  at  different  ages  of  the  individ- 
ual, the  pulp-chambers  vary  greatly  in  size  and  shape ;  yet,  with 
the  knowledge  derived  from  observations  made  on  other  teeth, 
as  well  as  from  the  chart  published  by  Arkovy,*  we  may  regard 
the  above  teeth  as  normal  for  the  age  of  twenty-two  years.  It 
is  likewise  established  that  the  pulp-chambers  of  the  teeth 
decrease  in  size  with  advancing  age,  and  especially  when  the 

*Diao-nostik  der  Zahnkrankheiten,  1885. 


THE    PULP-CHAMBERS    OF    THE    TEETH. 


31 


enamel  of  the  teeth  becomes  worn  away.  In  these  instances, 
not  only  all  the  horns  of  the  pulp  gradually  disappear,  but 
sometimes  almost  the  whole  pulp-chamber  becomes  obliterated 
by  the  formation  of  secondary  dentine.  This  condition  of  the 
pulp-chambers  does  not  so  much  depend  upon  the  age  as  upon 
the  habit  of  the  individual  to  whom  the  teeth  belong,  and  upon 
the  articulation  of  the  teeth.     Some  individuals,  especially  those 

Fig.  19. 


Key  to  the  Measurements  of  the  PtTLP-CH.iiiBERS  of  the  Teeth. 

A.  sctfiittal  section  of  the  rigid  lower  first  molar. — DN.  diameter  of  neck  ;  DP,  diameter  of 
pulp-ehamber ;  a,  diameter  between  pulp-chamber  and  mesial  surface:  h,  diameter  between 
anterior  horn  of  pulp-chamber  and  external  surface  of  cusp  :  c.  diameter  between  posterior 
horn  of  pulp-chamber  and  external  surface  of  cusp ;  d,  diameter  between  the  pulp-chamber 
and  distal  surface.  ^,  frontal,  section  of  tlie  left  lower  first  molar. — Z>iV,  diameter  of  neck  ; 
DP,  diameter  of  pulp-chamber:  a,  diameter  between  pulp-chamber  and  buccal  surface;  h, 
diameter  between  buccal  horn  of  pulp-chamber  and  external  surface  of  cusp :  c.  diameter 
between  lingual  horn  of  pulp-chamber  and  external  surface  of  cusp  ;  d,  diameter  between  pulp- 
chamber  and  lingual  surface. 


of  a  nervous  temperament,  have  the  habit  of  griuding  their  teeth 
during  sleep,  whereby  the  enamel  of  the  antagonizing  surfaces 
soon  becomes  worn  off.  In  other  instances  a  person  loses  some 
of  the  molars  and  bicuspids,  with  the  result  that  he  is  able  to 
masticate  with  the  front  teeth  only,  in  which  case  the  enamel  of 
these  teeth  is  soon  worn  away.  In  such  cases,  we  observe  in  the 
vicinity  of  the  pulp-chamber  corresponding  to  the  place  of  injury 


32 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


on  tlie  grinding-  or  cutting-surfaces  of  the  teeth,  a  formation  of 
secondary  dentine,  although  the  individual  may  not  be  more 
than  thirty  or  thirty-five  years  of  age.  On  the  other  hand,  it 
sometimes  occurs  that  with  people  from  forty-five  to  fifty-five 
vears  of  age  there  remains  a  complete  set  of  teeth,  with  their 
cusps,  as  well  as  the  horns  of  the  pulp,  still  present.  Further- 
more, where  we  find  defects  upon  the  neck  of  the  tooth,  called 
erosion,  we  observe  a  great  diminution  in  the  size  of  the  pulp- 
chamber,  and  especially  that  portion  corresponding  to  the  place 
of  injury  in  the  neck  of  the  tooth.  In  some  chronic  constitu- 
tional diseases,  particularly  in  anaemia,  we  often  meet  with  teeth 
the  pulp-chambers  of  which  are  unusually  large. 

Notwithstanding  the  great  dilferences  existing  in  the  size  and 
form  of  the  pulp-chambers  of  the  teeth,  it  is  of  great  value  to 
know,  approximately,  the  thickness  of  the  dental  tissue  between 
the  pulp-chamber  and  the  periphery  of  the  tooth,  and  conse- 
quently the  author  has  made  correct  measurements  of  the  thirty- 
two  teeth  in  twelve  different  places,  as  explained  by  Fig.  19,  ^ 
and  B. 

Table  of  Measurements  of  Puljp-Chamhers  in  Millimeters. 


IS 

Labial  Sections,  respectively  Buccal 
or  Sagittal. 

02 

OS 

1 

klesial 

or  Frontal  Sections. 

s 
'^ 

a 
2.1 

b 

" 

d 
2.1 

D  P 
2.9 

DN 

7.1 

a 

6 

e 

d 

DP 

D  N 

1 

4.7 

4.6 

9 

23 

4.1 

2.6 

1.6 

6.5 

2 

2.0 

5.4 

5.6 

2.3 

8.5 

7.8 

10 

1.9 

5.6 

2.0 

1.9 

5.8 

3 

2.8 

4.8 

5.0 

2.4 

2.3 

7.5 

il 

2.5 

5.8 

... 

2.8 

2.2 

7.5 

4 

2.0 

4.7 

2.1 

1.0 

5.1- 

12 

1.6 

3.9 

4.5 

2.1 

4.6 

8.3 

5 

1.9 

4.9 

1.7 

1.0 

4.6 

13 

2.0 

5.2 

5.8 

2.3 

4.2 

8.5 

6 

2.1 

6.9 

2.4 

1.5 

6.0 

14 

3.4 

5.5 

5.4 

3.2 

4.6 

11.2 

7 

1.6 

3.6 

1.7 

1.5 

4.8 

15 

3.4 

5.4 

6.4 

2.4 

5.6 

11.5 

8 

2.4 

6.5 

2.2 

1.9 

6.5 

16 

2.5 

5.5 

5.8 

2.4 

59 

10.8 

25 

1.4 

4.1 

... 

1.6 

1.0 

4.0 

17 

2.2 

5.1 

4.9 

2.5 

3.2 

7.9 

26 

1.6 

4.0 

1.7 

0.8 

4.0 

18 

2.4 

6.3 

7.0 

2.1 

43 

8.8 

27 

1.9 

6.1 

2.4 

1.0 

5.1 

19 

2.3 

5.0 

6.2 

2.0 

4.4 

8.7 

28 

2.0 

3.5 

1.8 

0,9 

4.7 

20 

1.3 

4.0 

5.1 

2.5 

2.5 

6.8 

29 

1.8 

4.0 

2.0 

1.2 

50 

21 

1.7 

4.7 

4.4 

1.9 

2.5 

6.1 

30 

2.4 

5.1 

4.9 

2.5 

3.6 

8.5 

22 

2.6 

4.4 

2.7 

2.5 

7.8 

31 

2.3 

5.4 

6.5 

2.5 

3.8 

8.6 

23 

2.0 

3.5 

2.4 

2.1 

6.5 

32 

2.2 

5.2 

6.0 

2.6 

33 

8.1 

24 

1.8 

3.8 

2.1 

1.3 

5.3 

THE    PULP-CHAMBERS    OF    THE    TEETH. 


33 


TaELE    of    MEASrREMEXTS    REGARDING    THE    SITUATION    OF    THE    HORXS    OF 

THE  Pulp. 


o2. 


P  o 


«  S 

ffi  <s 
O 

H2 


IS- 

■-J  g 

a 
&-0 


P  go 


e-S 


3  & 

OS- 


LOWER TEETH.                  UPPER  TEETH. 

A  man  17  years  of  "> 
age  with  normally  j- 
developed  teeth.     ) 

A  man  33  years  of  ) 
age  with  normally  >- 
developed  teeth.    } 

A   man  37  year.s  of  ] 
age     with     teeth  >■ 
very  much  worn.  J 

A   man  17  years  of] 
age  with  normally  > 
developed  teeth.     ) 

A   man  33  years  of") 
age  with  normally  r 
developed  teeth.     J 

A  man  37  years  of  1 
age     with     teeth  r 
very  much  worn.  ) 

1 

1              1                  1                  1                       1                  1                -^ 

n: 

1 

CO 

o 
p 

.*-*             .=■-*             .*-*                   1                  1                .•» 

Di*                     *                     *                        lid 

p" 

1                 jn                   0-.                    *-                         *.                                          J^ 

!                                                  Vt                                                                                            1 

-. 

E 

cn                       Oi                       W                              ii                       J-                      *. 

F    1 

Cji                       p                       Oi                                1                           1                        *. 

=    ' 

o 

2 

o 
p" 

\n                   '                       '                             :.T                    ^-1                   ' 

P 

i                       p,                           O.                           *-                                     4-                           _.*.                          ^ 
1                                                                                                                                     «                             * 

K 

ra 

f'                f'                f~                     9^                f^               ^ 

P* 

J-                       Oi                       J-                              J~                       ^                      en 
i.T                  C7I                  C.T                        bi                  en                  ' 

S-. 

2 
1 

1 

rf^                           >(>.                           ^                                    -L.                            4^                          4^ 

p" 

o«                  cj>                  *.                        :ri                  4-                  *- 

ni 

1 

,                  4^                     C»=                     CO                           *-                     *-                    w 

1                    ■                          en                       ■                                 '                          '                         bi 

» 

_*-                     _i.'i                     *^                           ^                     en                    4>. 
V»                  '                     en                        ui                                       en 

^ 

1 
2d  Bicusp. 

00                            —                           05                                    4>.                           *^                          W 

j                in                  ■                     ■                           ■                     en                  en 

p* 

]                4-                  4-                   o;                         4-                  en                  *- 

p: 

1st  Bicusp. 

;                 4-                    ^                    i;                          j_                    4>.                   CO 
1                ■                     en                   ■                           ■                     ■                    en 

p 

■                ji.                  *.                  (o                        4-                  en                  CO 
en                    "en                          ■                       "                     en 

Cuspid. 

i                        4-                           _4-                            o;                                    4-                           C-.                          CO 

1                  "                        cn                     ■                               en                     '                        * 

Lateral  Incisor. 

4-                    en                    tc   .                      en                   -a                   Co 

bi 

Central  Incisor. 

CO                       en                      ls3                              en                      ~4                      CO 

Central  Incisor. 

CO                  en                  CO                        en                  Oi                  CO 

bi                  ■                     ■                           ... 

Lateral  Incisor. 

4^                           4^                           CO                                    4^                           en                          |sS 

b" 

Cuspid. 

4^                         CO                         CO                                4a.                         en                        CO 

bi 

p" 

1st  Bicusp. 

*-                           4^                           CO                                    *,.                           4^                          rf^ 

bi                       ■                   bi                ■ 

::: 

:                 CO                    en                    cc                          CO                    en                   CO 
bi                  '                     bi                        bi                  '                    en 

p 

2d  Bicusp. 

en                         4^                         4-                                CO                         ^                        4.- 

bi 

=r. 

4^                   CO                    CO                          *-                   en                   co 
bi                   bi                          "                      '                      bi 

p 

s 

5 

p* 

y1 

*-                  en                  4>-                        en                  *-                  CO 
bi                  ■                     ■                           ■                     ■                    b" 

=-. 

*.                   4^                   jP^                          *.                    en                   *- 

p 

1 

4^                  ^                  4>.                        .^                  en                  en 
en                  en                  bi                        en                  en 

*-                  en                  4k                        en                  O'                  *- 

1     P 

p* 

4*.                      O                       *.                              ZJi                       pi                      f- 
cn    -                                      b»                          *    *                     *                cn^ 

*..                   *-                   4a.                         en                    ej'                   4* 
bi                  h<                        bn                  ■                     ■ 

P 

en                    C-.                     I                             111 

-• 

en                  en                   1                           1                    P"                   1 

P 

^ 

'  g 

p" 

Ol                       Oi                        ,                                 1                         •'^                       1 
1                             1                     en     .              1 

1     = 

en*                 o.                     1                             111 

1     ^ 

D 

1                     g                     1                             111 

1     =^ 

H 

i^ 

a 

p 

^ 

3 

hi 

R 

M 

9 

ij 

>  4 


S"   iz! 

►1       Q 


34 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


CHAPTEE   VL 


THE  ARTICULATION  OF  THE  TEETH. 


When  we  examine  the  occluding  surfaces  of  a  perfect  set  of 
human  teeth  and  the  manner  in  which  they  articulate,  we  come 
to  the  conclusion  that  the  articulation  of  the  teeth  is  a  most 
wonderful  device  of  nature,  forming  quite  a  complicated  piece 
of  mechanism.  The  principles  of  articulation,  both  from  a 
practical  and  a  scientific  standpoint,  are  of  the  greatest  impor- 
tance, and  therefore  ought  to  be  studied  closely  by  every  dental 
student.  The  articulation  of  the  teeth  is  based,  upon  certain 
geometrical  and  mechanical  laws  first  described  by  W.  G.  A, 
Bon  will.* 

Fig.  20. 


Articulation  of  a  Perfect  Set  of  Teeth  of  the  Right  Side— External  Surface. 


In  observing  this  articulation,  we  find  that,  in  the  human  jaw, 
a  straight  line  drawn  from  the  buccal  surface  of  the  first  bi- 
cuspid to  the  internal  angle  of  the  condyloid  process  of  the  lower 
maxilla  will  almost  touch  all  the  buccal  surfaces  of  the  bicuspids 
and  molar  teeth.  Tliis  shows  that  the  teeth  named  are  arranged 
in  an  almost  straight  row  from  the  cuspid  to  the  inner  angle  of 
the  condyloid  process  of  the  lower  jaw.  We  also  observe  that, 
with  the  exception  of  the  upper  third  molars,  every  tooth  articu- 
lates with  two  in  the  opposing  jaw.  (See  Figs.  20  and  21.) 
Thus,  if  a  tooth  is  lost,  the  antagonist,  being  retained  in  its 
position,  is  useful  to  a  certain  extent,  and  the  regularity  of  the 

*  '^Tlie  Geometrical  and  Mechanical  Laws  of  the  Articulation  of  the  Human 
Teeth."     HaiTis'.s  •■Principles  and  Practice,''  twelfth  edition 


THE    ARTICULATION    OF    THE    TEETH. 


35 


dental  arch  is  not  materially  disturbed.  Again,  articulation 
has  been  wisely  arranged  in  this  manner  to  offset  the  work  of 
another  law  of  nature,  by  the  operation  of  which  every  tooth 
not  articulating  with  at  least  one  opposing  tooth  gradually  elon- 
gates, and  eventually  is  cast  out  of  the  jaw.  We  observe  that, 
in  a  normal  articulation,  all  the  teeth  of  the  upper  jaw  more  or 
less  overlap  those  of  the  lower,  although  it  must  be  admitted 
that  a  perfectly  articulating  set  of  teeth  is  a  rarity  in  the  human 
mouth.  In  studying  the  articulation  of  the  bicuspids  and 
molars,  we  find  that  every  cusp  correctly  fits  between  cusps  in 
the  opposing  jaw ;  and  by  this  arrangement  of  cusps  and  depres- 
sions the  grinding-surface  is  materially  increased.  The  external 
or  buccal  cusps  of  the  upper  bicuspids  and  molars  are  arranged 
a  little  outside  of  the  lower  arch, — a  disposition  which  enables 

Fig.  21. 


Articulation  of  a  Perfect  Set  of  Teeth  of  the  Right  Side— Internal  Surface. 

the  teeth  of  the  upper  jaw,  when  the  pterygoid  muscles  are 
brought  into  action,  to  articulate  with  all  the  teeth  of  the  lower 
jaw.  The  lingual  cusps  of  the  upper  bicuspids  and  molars  are 
somewhat  higher  and  less  pointed  than  the  corresponding  outer 
cusps.  In  the  lower  teeth  we  find  this  arrangement  reversed, 
and  observe  that  the  outer  cusps  of  the  bicuspids  and  first 
molars  are  the  longer  and  rounder,  while  the  inner  or  lingual 
cusps  are  the  shorter  and  more  pointed.  The  result  of  this 
reciprocation  evidently  is  that,  when  the  lower  jaw  is  moved 
laterally  by  the  pterygoid  muscles,  the  buccal  and  lingual 
cusps  of  the  upper  teeth  on  one  side  of  the  mouth  play 
upon  the  buccal  and  lingual  cusps  of  the  lower  teeth,  while 
the  lingual  cusps  of  the  upper  jaw  on  the  opposite  side  of 
the  mouth  articulate  with  the  buccal  cusps  of  the  lower  teeth. 


36  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

Hence  the  teeth  not  only  possess  a  larger  extent  of  grinding- 
surface  with  small  proportional  bulk,  but  considerable  energy  is 
saved  in  mastication.  At  the  same  time,  the  pressure  upon  the 
teeth  exerted  by  the  muscles  of  mastication  is  more  or  less 
equalized  through  the  entire  dental  arch.  If  we  examine  dif- 
ferent sets  of  teeth,  we  shall  notice  that  great  variations  exist 
in  the  lengths  of  the  so-called  overbites.  If  the  upper  front  teeth 
overlap  the  lower  ones  but  little,  we  invariably  find  short  cusps 
upon  the  bicuspids  and  first  molars,  while,  on  the  contrary,  when 
the  overbite  is  long  these  cusps  are  long  and  pointed,  provided 
all  the  teeth  occupy  their  proper  positions.  On  examining  the 
plane  of  the  grinding-surface  of  the  lower  bicuspids  and  molars, 
we  find  that  the  second  and  third  molars  stand  considerably 
higher  than  the  first,  yet  the  three  crowns  form  a  gradual 
slope.  Regarding  the  position  of  the  roots  of  the  low^er  second 
and  third  molars,  we  observe  that  while  their  crowns  are  tilted 
forward,  their  roots,  on  the  contrary,  are  directed  toward  the 
condyloid  process  of  the  jaw,  by  which  arrangement  this  grad- 
ual slope  is  accomplished.  In  consequence  of  this  slope  in  the 
low^er  dental  arch,  the  second  and  third  molars  of  the  upper  jaw 
also  assume  a  slanting  position  upward,  rendering  the  first  upper- 
molar  the  longest  of  the  molar  teeth.  The  object  of  this  arrange- 
ment evidently  is  that,  when  by  the  sliding  movements  of  the 
lower  jaw  the  condyloid  process  is  brought  forward,  the  second 
lower  molar  articulates  against  the  first  upper  one,  which,  being 
longer  than  the  second  and  third,  opens  the  jaw  sufficiently  to 
allow  the  articulation  of  the  cutting-edges  of  the  upper  and  lower 
front  teeth  as  well  as  the  points  of  the  cusps  of  the  bicuspids. 
Hence  the  pressure,  which  otherwise  would  bear  upon  the  molars 
only,  is  equally  distributed  upon  the  side  as  well  as  the  front  por- 
tion of  the  dental  arch. 

When,  because  of  the  loss  of  the  back  teeth,  a  patient  for  a 
number  of  years  masticates  entirely  with  the  front  teeth,  the 
muscles  of  mastication  gradually  become  contracted,  the  condy- 
loid process  leaves  its  normal  place  in  the  glenoid  fossa,  and 
occupies  a  more  anterior  position.  In  such  cases  we  observe  a 
slight  protrusion  of  the  lower  jaw,  and  the  remaining  teeth  to 
be  considerably  reduced  in  length  through  mechanical  abrasion, 
brought  about  by  the  lateral  movements  of  the  lower  jaw^. 
Their  cutting-edges,  formerly  more  or  less  sharp,  are  now 
Inroad  and  flat,  similar  in  form  to  the  grinding-surface  of  a 


THE  ARTICULATION  OF  THE  TEETH. 


37 


much-worn  bicuspid.  In  this  instance  an  acquired  abnormal 
articulation  of  the  lower  jaw  is  present,  which,  upon  the  restora- 
tion of  the  teeth  to  their  original  length,  will  cause  the  condy- 
loid processes  of  the  lower  jaw  to  resume  their  former  position 
in  the  glenoid  fossie. 

From  the  article  published  by  W.  G,  A.  Bonwill  I  quote  the 
following : 

"  The  Equilateral  Triangle  ivithin  the  Main  Triangle. — The  out- 
line drawing  (Fig.  22)  may  be  thought  ideal.  But  any  one  at 
all  acquainted  with  geometry  must  be  struck  with  wonder 
at  the  marvelous  ingenuity  of  the  contrivance  based  alone  on 
the  equilateral  triangle.     It  will  be  seen  that  perfection  must 

Fig.  22. 


Diagram  showing  Equilateral  Triangle  of  the  Lower  Jaw.    (After 
W.  G.  A.  Bonwill.) 


be  the  result,  since  each  part  is  complete  within  itself  and  the 
whole  supporting  each  individual  part. 

"  How  have  I  arrived  at  this  divination  ?  The  law  is  based 
upon  the  measurement  of  over  two  thousand  human  skulls. 
First  make  an  equilateral  triangle,  four  inches;  A,  A,  F. 
Draw  a  line  from  T  to  F.  What  is  the  guide  to  form  the  arch  ? 
Know  the  actual  width  of  the  superior  central,  lateral,  and  cuspid 
at  their  greatest  diameter  from  the  mesial  to  distal  surfaces,  say 
H",  as  in  Fig.  22.  Measure  this  off  with  the  dividers,  and 
place  one  arm  at  F  and  describe  an  arc  from  D  to  D  through  I. 
Then  place  dividers  at  I,  and  intersect  the  line  just  made  from 


88  THE    ANATOxMY    AND    PATHOLOGY    OF    THE    TEETH. 

F,  and  it  will  be  found  that  at  D  will  be  found  the  extremest 
point  of  the  arch  D,  F,  D,  and  will  be  the  distal  surface  of  the 
superior  cuspid.  Place  the  dividers  at  I,  and  describe  the  arc 
from  D  to  D  through  F,  which  will  constitute  the  normal  and 
positive  arch  of  the  superior  jaw.  There  wall  be  an  equilateral 
triangle  from  D,  F,  I  on  either  side  of  the  mesial  line  at  F. 
The  same  will  be  found  the  base  of  each  superior  incisor. 

"  I^ext  draw  a  line  from  A  to  D  on  either  side,  which  will  be 
the  guide  for  the  bicuspids  and  molars  as  to  width  and  depth. 
Then,  by  placing  the  dividers  at  A  and  B,  describe  another  arc 
to  C,  which  will  give  the  width  of  iirst  superior  bicuspid.  The 
line  from  A  to  D  passes  through  its  palatal  base,  and  will  pass 
through  center  of  base  of  triangle  of  this  tooth.  Form  another 
triangle  by  drawing  a  line  from  H  to  H,  through  B,  which  wnll 
pass  through  the  center  of  the  first  molar,  and  will  give  the 
width  between  the  palatal  surfaces  or  their  depth  or  thickness. 
Placing  the  dividers  at  I  and  F,  we  intersect  the  line  from  F  to 
T  at  Y.  Draw  a  line  through  Y  to  E,  E,  forming  another  equi- 
lateral triangle.  From  B  to  F  is  now  the  radius  of  another 
arc,  which  intersects  the  line  from  D  to  A  at  Y,  and  the  line  A 
to  D  at  0.  A  line  now  drawn  E  to  E  through  Y  intersects  the 
center  of  the  second  molar  at  E,  E. 

"  Get  half  the  distance  between  the  points  at  E  on  the  line 
from  D  to  A,  and  the  width  of  the  first  molar  is  made,  and  also 
the  second,  which  is  the  angle  of  the  equilateral  of  each.  This 
leaves  room  between  the  first  bicuspid  and  first  molar,  and  is 
the  width  of  second  bicuspid ;  or  it  is  shown  by  placing  the  di- 
viders at  A  and  Y,  and  intersecting  line  from  D  to  A  at  W,  same 
as  from  B  to  C,  for  the  first  bicuspid's  width.  The  distance 
from  D  to  D  is  the  same  as  from  D  to  the  distal  surface  of  the 
second  molar.  P  to  P  through  Z  forms  another  equilateral  tri- 
angle, giving  the  wisdom-tooth's  place  in  the  arch. 

"  The  arrangement  of  L  and  J  on  the  left  shows  the  teeth  in 
the  act  of  mastication,  while  on  the  right  the  inner  cusp  of 
molars  of  the  upper  and  outer  of  the  low^er  molars  come  in  con- 
tact when  not  in  use.  There  is  double  the  surface  touching  at 
every  lateral  movement." 


GENERAL    AXATOMY    OF    THE    HUMAN    TEETH.  39 

CHAPTER    VIL 

WENERAL  ANATOMY  OF  THE  HUMAN  TEETH. 

I.  The  sockets  of  the  teeth  are  made  up  of  a  thin  layer  of 
cortical  bone,  distinctly  lamellated,  and  blending  with  trabeculse 
of  the  cancellous  bone  in  the  central  part  of  the  alveolar  pro- 
cess. The  latter  we  find  filled  with  freely  vascularized  medul- 
lary tissue  in  the  juvenile  condition  ;  whereas,  in  advanced  age, 
this  tissue  is  transformed  into  fat,  which,  as  a  rule,  is  likewise 
supplied  with  numerous  blood-vessels.  The  socket-walls  are  of 
the  greatest  possible  strength,  with  the  least  mass,  since  a  hollow 
cylinder  is  stronger  than  a  solid  one.  The  blood-vessels  of  the 
medullary  spaces  are  continuous  with  those  of  the  periosteum, 
pericementum,  and  gums.  This  explains  why  sockets  easily 
become  necrotic  after  suppurative  periostitis  and  pericementitis, 
in  event  of  which  maladies  a  certain  amount  of  the  socket  is 
deprived  of  the  nourishing  material  carried  to  it  by  the  blood- 
vessels.    (See  Fig.  23.) 

II.  The  compact  hone  of  the  socket  is  covered  with  a  layer  of 
dense  connective  tissue  of  broad  bundles.  This  is  continuous 
with  another  layer  of  fibrous  connective  tissue  composed  of 
bundles  that  run  obliquely  toward  the  apex  of  the  root  of  the 
tooth.  The  latter  tissue  bears  the  name  of  pericementum,  root- 
mem.brcme,  or  alreolar  dental  periosteum.  Its  bundles  are  firmly 
attached  to  the  walls  of  the  socket  and  the  root  of  the  tooth. 
Thus  it  becomes  comprehensible  that  the  teeth  can  stand  enor- 
mous pressure  without  injury,  as  in  the  process  of  mastication, 
in  the  lifting  of  heavy  weights,  or  in  the  suspension  of  the 
whole  body  on  a  rope,  by  means  of  the  dentures.  We  further- 
more understand  why  sometimes  a  portion  of  the  bony  structure 
is  carried  away  upon  the  extraction  of  a  tooth.  At  the  same 
time  the  pericementum  gives  a  considerable  degree  of  elasticity 
and  a  limited  amount  of  mobility  to  the  teeth.  This  explains 
the  presence  of  facets  upon  the  approximal  surfaces  of  the  crowns 
of  teeth  in  crowded  dental  arches. 

III.  Similarly  the  upper  and  the  lateral  portions  of  the  alveolar 
process  are  covered  by  fibrous  connective  tissue,  the  periosteum , 
which  blends  with  the  dense  fibrous  connective  tissue  of  the 
gum,    composed    of    broad    and   straight   interlacing   bundles. 


40 


THE    ANATOMY    AND    PATHOLOGY    OF   THE    TEETH, 


This  firm  cushion,  the  (/".in,  in  a  normal  condition  is  but  scantily 
supplied  with  blood-vessels.  The  superficies  of  the  gum 
exhibit  numerous  finger-like  elevations,  the  so-called  papillae, 


Fig.  23. 


Diagram  of  the  Structure  and  Implantation  of  a  Normal  Incisor  Tooth. 

L,  cuticle  of  enamel,  Nasmyth's  membrane ;  E,  enamel ;  D,  dentine  with  uniformly  dis- 
tributed canaliculi ;  /,  interzonal  layer  between  enamel  and  dentine  ;  B,  border-line  between 
enamel  and  cementum  of  neck  ;  5,  cementum  of  neck  ;  Ce.  cementum  of  root ;  Z,  interzonal 
layer  between  dentine  and  cementum  ;  P,  pericementum  ;  A,  arteriole  of  pulp,  brancbing  into 
capillaries;  F,  vein  of  pulp,  taking  up  capillaries;  xV,  meduUated  nerve-fibers  of  pulp:  Eg, 
stratified  epithelium  of  gum  ;  P^r,  papillary  layer  of  gum  ;  Pe,  periosteum  ;  Co,  cortical  bone 
of  alveolus  or  socket;  6'a,  cancellous  bone-tissue  of  alveolus;  ilf,  medullary  spaces  of  can- 
cellous bone. 


GENERAL  ANATOMY  OF  THE  HUMAX  TEETH.         41 

which  contain  loops  of  capillary  blood-vessels.  The  sum-total 
of  the  papillse  is  termed  the  papillan/  layer.  At  its  outer  surface 
it  is  covered  with  a  layer  of  stratified  epithelia.  In  the  strata 
we  observe  three  forms  of  epithelia,  as  in  the  skin  and  in  the 
mucous  membranes  generally.  The  innermost  layer  is  made  up 
of  a  single  row  of  columnar  epithelia,  much  elongated  in  a  ver- 
tical direction  and  resting  upon  the  connective  tissue.  This  row 
of  columnar  epithelia  is  covered  by  several  rows  of  cuboidal 
epithelia,  so  termed  on  account  of  their  shape.  The  layers  of 
cuboidal  epithelia  are  coated  by  several  strata  of  flat  or  pave- 
ment-epithelia,  so  called  because  their  length  and  width  are 
much  greater  than  is  their  thickness.  The  pavement  layer  is 
composed  of  a  horny  substance,  and  it  exhibits  properties  of 
life  only  in  the  nuclei  of  the  epithelia,  the  same  being  the  case 
throughout  the  flat  epithelial  covering  of  the  oral  cavity.  The 
surface  of  the  gum  appears  to  the  naked  eye  either  smooth  or 
slightly  granular,  since  the  papillary  elevations  of  the  connective 
tissue  and  the  valleys  between  them  are  but  slightly  pronounced 
upon  the  epithelial  surface.  Continued  irritation,  as  in  the  too 
frequent  application  of  the  tooth-brush,  is,  in  many  instances, 
sufficient  to  give  the  surface  of  the  gums  a  more  or  less  pro- 
nounced papillary  aspect. 

lY.  Dentine  is  the  tissue  which  composes  the  main  mass  of  the 
tooth.  It  consists  of  a  glue-yielding  basis-substance  (not  carti- 
laginous, as  is  often  stated),  richly  infiltrated  with  lime-salts. 
The  chemical  constituents,  according  to  Bibra,*  of  perfectly 
dried  dentine  are, — 


Organic  matter  (tootli-caitilage)         .... 

27.61 

Fat 

0.40 

Phospli.  iluoride  calcium 

66.72 

Carbonate  of  calcium 

3.36 

Phosphate  of  magnesium  ...... 

1.08 

Other  salts 

0.83 

The  basis-substance  is  traversed  by  the  dentinal  canaliculi, 
which  take  their  general  course  from  the  pulp-chamber  toward 
the  summit  of  the  crown,  running  horizontally  in  the  neck, 
and  in  a  portion  of  the  root.  It  is  only  near  the  apex  that  the 
canaliculi  are  inclined  toward  the  end  of  the  root.  Each  canali- 
culus curves  in  the  general  shape  of  the  letter  S,  slightly  toward 
the  pulp-chamber  and   abruptly  toward   the  periphery  of  the 

*  From  Tomes 's  ••  Dental  Anatomv." 


42  THE    ANATOxMY    A^'D    PATHOLOGY    OF    THE    TEETH. 

dentine.  In  the  region  of  the  crown,  upon  approaching  the  peri- 
phery of  the  dentine,  almost  without  exception,  the  canaliculi 
divide  into  tw^o  or  three  branches,  this  branching  being  termed 
bifarcatioiL  In  the  region  of  the  neck  such  a  bifurcation  of 
the  dentinal  canaliculi  is  exceptional.  It  is  a  peculiarity  there 
that  the  canaliculi  do  not  reach  the  periphery  of  the  dentine,  but 
stop  short  of  the  latter  at  a  distance  varying  in  difi'erent  teeth, 
w^hereas  in  the  root  bifurcation  is  of  frequent  occurrence. 

Each  dentinal  canaliculus  contains  a  slightly  beaded  fiber,  the 
deritinol  fibrilla,  or,  in  honor  of  the  discoverer,  ./.  Tomes\s  fiber. 

In  the  crown  the  dentine  is  surrounded  by  the  enamel,  and 
in  the  regions  of  the  neck  and  root  by  the  cementum.  The 
border-line  between  these  tissues  has  been  termed  by  W.  H. 
Atkinson  the  interzonal  lagev.  This  layer  has  been  also  termed 
the  granular  hnjer  by  J.  Tomes.  It  is  usually  marked  by  shallow 
excavations  along  the  periphery  of  the  dentine.  Occasionally 
the  ultimate  branches  of  some  dentinal  canaliculi  transgress  the 
interzonal  layer,  producing  either  loops  or  club-shaped  enlarge- 
ments in  the  adjacent  portion  of  the  enamel.  The  interzonal 
layer  between  the  dentine  of  the  root  and  the  adjacent  cementum 
may  be  marked  by  shallow  excavations  similar  to  those  in  the 
dentine  of  the  crown,  or  there  may  exist  no  distinct  boundary 
line  between  the  two  tissues. 

V.  Enamel.  Whereas  dentine  is  undoubtedly  a  form  of  con- 
nective tissue  closely  allied  to  bone,  enamel  bears  no  resemblance 
to  any  other  tissue  in  the  animal  organism.  It  starts  from  epi- 
thelium, becomes  transformed  into  connective  tissue,  yet  exhibits 
features  characteristic  of  epithelial  structures.  The  enamel 
covers  only  the  crown  of  a  tooth.  It  is  thickest  upon  the  sum- 
mit of  the  crown,  gradually  becoming  thinner  toward  the  region 
of  the  neck,  "where  it  terminates  in  a  sloping  line,  slightly  over- 
lapped by  the  cementum.  The  enamel  is  composed  of  so-called 
enamel-prisms,  exhibiting  transverse  striations,  the  striee  of  Retzius. 
Between  these  enamel-prisms  there  are  narrow  interstices  which 
hold  delicate  beaded  fibers,  the  enamelfibrillce.  The  enamel- 
prisms  run  a  wavy  course,  and  we  meet  with  transverse  sections 
intermixed  wdth  longitudinal  ones  so  frequently  that  the  idea  of 
interlacing  bundles  of  enamel-prisms  forced  itself  upon  previous 
investigators.  Frank  Abbott  was  the  first  to  assert  that  no 
such  interlacing  occurs,  and  that  the  appearance  of  transverse 
sections  intermixed  with  longitudinal  ones  is  due  to  the  pro- 


GENERAL  ANATOMY  OF  THE  HUMAN  TEETH.         43 

nouncedly  wavy  course  of  some  of  the  bundles,  being  cut  both 
longitudinally  and  transversely. 

The  outer  surface  of  the  enamel  is  covered  by  a  thin,  horny 
layer  of  epithelial  tissue,  the  so-called  XasmijiJi's  membrane,  or 
enamel-cuticle.  This  layer  can  be  rendered  visible  by  the  appli- 
cation of  strong  chemical  agents,  and  is  present  only  in  teeth 
not  as  yet  worn  off  by  mastication.  It  is  in  direct  union  with 
the  outermost  epithelial  layer  of  the  gum,  which  is  likewise 
composed  of  flat,  hornitied  epithelia,  to  a  varying  degree.  The 
enamel-cuticle  is,  therefore,  the  only  laj^er  which  closes  up  the 
fissure  between  the  neck  of  the  tooth  and  the  adjacent  gum. 

VI.  Cementum.  This  is  a  stratum  of  bone-tissue  covering  the 
dentine  of  the  root  of  the  tooth.  It  starts  in  an  oblique  line  at 
the  neck,  gradually  increasing  in  thickness  toward  the  apex, 
where  it  borders  upon  the  beginning  of  the  root-canal.  The 
cementum  is,  as  a  rule,  covered  at  its  outer  periphery  by  a  single 
layer  of  calcified  protoplasmic  bodies,  similar  to  the  so-called 
osteoblasts  (Gegenbaur),  which  are  in  connection  with  the  fibrous 
connective  tissue  of  the  pericementum.  At  the  neck  it  is  com- 
posed of  a  calcified  basis-substance,  pierced  by  spindle-shaped 
protoplasmic  bodies.  In  the  root  portion  of  the  cementum  we 
observe  a  distinct  lamellation,  and  here  we  meet  with  numerous 
branching  protoplasmic  bodies,  the  cement-corpuscles,  bearing  a 
close  resemblance  to  bone-corpuscles.  Even  in  low  amplifica- 
tions by  the  microscope  we  frequently  notice  a  union  of  the 
ends  of  the  dentinal  canaliculi,  with  oftshoots  of  cement-corpus- 
cles. From  these  facts  we  may  infer  that  each  root  of  a  tooth 
represents  a  large  Haversian  system,  in  which  the  Haversian 
canal  corresponds  to  the  central  pulp-canal  and  its  soft  tenants, 
whereas  the  outermost  laj'er  of  the  cementum  represents  the 
concentrically  lamellated  cortex.  Between  these,  two  layers  is 
inserted  a  broad  layer  of  dentine,  traversed  by  dentinal  canaliculi, 

,  which  we  may  consider  as  elongated  oftshoots  of  bone-corpus- 
cles. If  viewed  in  this  light,  dentine  may  justly  be  considered 
a  modified  bone-tissue,  peculiar  to  the  structure  of  the  teeth. 

VII.  The  Pulp.  The  central  cavity  is  called  pulp-chaniber  in 
the  crown,  and  root-canal  in  the  root  of  a  tooth.  It  is  filled  5vith 
a  myxomatous  connective  tissue,  in  which  are  distributed  blood- 
vessels and  nerves.  These  enter  the  pulp-canal  at  the  apex  of 
the  root  of  the  tooth.  At  about  the  middle  of  the  root-canal 
a  small  afierent  artery,  the  arteriole,  splits  up  into  capillaries, 


44  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

producing  throughout  the  pulp-tissue  a  rich  net-work,  termin- 
ating at  the  summit  of  the  coronal  portion  in  loops.  The  capil- 
laries coalesce  with  the  vein.  This  vein  is  a  branch  of  the 
alveolar  vein,  into  which  it  carries  the  blood  through  the  root- 
canals.  There  is  a  large  number  of  bundles  of  nerves  in  the 
pulp,  entering  the  apical  foramen  in  the  shape  of  raedullated 
nerve-fibers.  Upon  approaching  the  periphery  of  the  pulp  they 
lose  their  medullary  sheaths  and  become  non-meduUated,  as  is 
the  rule  with  all  meduUated  nerve-fibers  in  peripheral  organs. 
During  the  development  of  the  tooth,  the  outer  surface  of  the 
pulp  exhibits  a  row  of  large  protoplasmic  bodies,  the  so-called 
odontoblasts  (J.  Tomes),  which  are  in  direct  connection  with  the 
tenants  of  the  dentinal  canaliculi.  In  the  fully-developed  tooth 
the  odontoblasts  are  not  always  present,  being  mostly  replaced 
by  irregular  rows  of  medullary  corpuscles.  The  ultimate  ter- 
mination of  the  nerve-fibrillee  can  be  traced  between  these  me- 
dullary corpuscles  or  odontoblasts,  but  never  to  a  direct  union 
with  the  dentinal  fibers.  This  fact  sufficiently  proves  that  the 
dentinal  fibers  are  not  true  nerves.  Lymph-vessels  are  un- 
questionably present  in  the  pulp,  but  nothing  positive  has  as 
yet  been  ascertained  as  to  their  course  and  origin. 

Anomalous  though  not  Pathological  Formations  in  the  Teeth 
(see  Fig.  24). — Among  the  most  frequent  occurrences  of  such 
formations,  we  notice  in  the  crown  of  the  tooth  fields  filled  with 
a  non-calcified  basis-substance.  They  are  known  as  the  inter- 
r/lobular  spaces  of  Czermak.  They  appear  as  irregular  spots, 
varying  in  size  and  shape,  but  always  bordered  by  concave  con- 
tours. These  so-called  spaces  occur  near,  though  never  directly 
at,  the  periphery  of  the  dentine  toward  the  enamel,  and  occa- 
sionally blend  with  much  smaller  spaces  at  the  interzonal  layer 
of  the  neck,  or  even  the  root  of  the  tooth.  They  are  traversed 
by  the  dentinal  canaliculi  without  the  slightest  deviation  of  the 
latter. 

Of  common  occurrence  in  the  dentine  are  fields  of  calcified 
basis-substance,  lacking  dentinal  canaliculi.  Much  rarer  are 
parallel  striations  of  the  dentine,  indicative  of  the  successive 
formation  of  the  layers  of  this  tissue. 

In  the  enamel  at  the  interzonal  layer  we  not  infrequently 
meet  w^ith  globular  or  club-shaped  spaces  filled  with  protoplasm. 
In  the  highest  expression  of  this  abnormality  we  find  every 
branch  of  the  dentinal  canaliculi  to  have  a  club-shaped  termina- 


GENERAL  ANATOMY  OF  THE  HUMAN  TEETH. 


45 


tion.  Pigmentation  and  stratification  of  the  enamel  are  not 
rare.  J.  Retzius  first  drew  attention  to  their  presence.  The 
brown  pigmentation  of  the  enamel  always  is  most  pronounced 

Fig.  21. 


Diagram  of  an  AyoMALous  though  sot  Pathological  Incisor  Tooth. 

6',  cuticle  of  enamel,  Nasmyth's  membrane :  E,  stratified  and  pigmented  enamel;  /,  inter- 
zonal layer  between  enamel  and  dentine,  with  club-like  terminations  of  dentinal  canaliculi : 
G,  dentine  with  interglobular  spaces  along  the  outer  periphery  :  -V,  cementum  of  neck,  over- 
lapping the  enamel;  5,  basis-substance  of  dentine,  destitute  of  canaliculi ;  .S' (upper),  stratifi- 
cation of  dentine;  S  (lower),  secondary  dentine;  Z.  interzonal  layer  between  dentine  and 
cementum,  with  club-like  enlargements  of  the  canaliculi;  Ce,  cementum  of  root;  P,  peri- 
cementum ;  0,  row  of  odontoblasts  at  the  outer  periphery  of  the  pulp  ;  M,  meduUated  nerves 
of  the  pulp;  Eg,  stratified  epithelium  of  gum;  Pa,  papillary  layer  of  gum;  So,  socket  or 
alveolus. 


46  THE    ANATOiMY   AND    PATHOLOGY    OF    THE    TEETH. 

along  the  periphery  and  along  the  strife  of  the  enamel.  What 
the  cause  of  such  pigmentations  and  stratifications  may  be,  we 
do  not  know. 

In  rare  instances  the  cement  of  the  neck  considerably  over- 
laps the  enamel.  This  feature  explains  certain  occurrences  in 
the  process  of  absorption  of  temporary  teeth.  Along  the  inter- 
zonal layer  between  the  dentine  and  the  cementum  we  occasion- 
ally meet  with  club-shaped  spaces  filled  with  protoplasm,  and  in 
union  with  the  terminations  of  the  dentinal  canaliculi.  All 
these  features,  including  the  interglobular  spaces,  may  be  con- 
sidered as  the  result  of  an  imperfect  calcification  during  the 
process  of  development. 


CHAPTER    VIII. 

GENERAL   HLSTOLOaY. 


The  animal  body  is  built  up  of  four  main  varieties  of  tissue, 
viz : 

I.   Connective  Tissue. 
IL,  Muscle-Tissue. 

III.  Nerve- Tissue. 

IV.  Epithelial  Tissue. 

According  to  the  views  of  most  histologists,  both  the  connec- 
tive and  muscle  tissues  are  products  of  the  mesoblast,  the 
middle  layer  of  the  germ,  and  the  nerve-tissue  originates  from 
the  epiblast,  whereas  the  epithelium  arises  from  both  the  epi- 
and  the  hypoblast.  This  view,  however,  cannot  be  strictly 
adhered  to,  since  we  know  that  the  central  nerve-organs,  though 
originally  products  of  the  epiblast,  in  further  development  are 
composed  of  a  tissue  of  their  own,  closely  allied  to  connective 
tissue.  The  enamel  of  the  teeth  is  of  an  epiblastic  or  epithelial 
origin,  but  during  further  development  it  changes  to  a  type  of 
connective  tissue. 

I.  Connective  Tissue. — This  tissue  composes  the  main  mass 
of  the  organism.  It  forms  the  bony  frame  or  skeleton,  the 
articular  surfaces  of  the  joints,  or  cartilages.  As  the  derma  of 
the  skin,  it  covers  the  body ;  as  perimysium  and  perineurium,  it 
accompanies  the  muscles  and  nerves ;  and  as  periosteum,  it  en- 


GENERAL    HISTOLOGY.  47 

velops  all  bones.  Fat  is  likewise  a  sub-variety  of  connective 
tissue.  The  latter  is  the  only  tissue  serving  as  a  carrier  of  both 
blood-  and  lymph-vessels. 

Up  to  the  year  1873,  connective  tissue  was  believed  to  be  made 
up  of  cells, — the  so-called  connective-tissue  corpuscles, — and  an 
apparently  inert  intercellular  or  basis-substance,  varying  con- 
siderably in  consistency  and  chemical  constitution.  This  basis- 
substance  generally  is  termed  glue,  a  nitrogenous  matter  for 
which  there  exists  as  yet  no  chemical  formula.  Until  that  time, 
also,  the  cells  were  believed  to  be  isolated  individuals,  imbedded 
in  cavities  of  the  basis-substance.  In  the  year  mentioned,  Carl 
Heitzmann  showed  that  protoplasm  in  general  pbssesses  a  reti- 
cular structure,  a  fact  which  has  since  been  proved  by  photo- 
micrography. In  the  basis-substance  Heitzmann  likewise  has 
shown  the  existence  of  a  reticulum  identical  with  that  of  the 
protoplasm,  a  fact  not  as  yet  generally  accepted  by  histologists. 
The  reticulum,  its  points  of  intersection,  the  granules,  and  the 
nucleus  are  the  living  or  contractile  matter  proper,  and  it  is  this 
which  pervades  the  basis-substance,  as  well  as  the  protoplasm. 
In  this  view^  both  the  animal  and  the  vegetable  organisms  are  a 
continuous  net-work  of  living  matter, — a  delicate  reticulum,  the 
meshes  of  which  are  filled  with  a  lifeless  nitrogenous  liquid  in 
the  protoplasm,  while  in  all  varieties  of  basis-substance  these 
meshes  contain  a  solid  or  semi-solid  nitrogenous  matter. 

We  distinguish  four  varieties  of  connective  tissue,  viz : 

A.  3Iyxomatous,  or  mucoid. 

B.  Fibrous,  or  striated. 

C   Cartilaginous,  or  chondrogenous. 

D.   Osseous,  or  bong. 

Under  the  last  head  belong  the  dentine  and  the  ceinentuni  of  the 
teeth.  While  the  character  of  any  variety  of  connectire  tissue  is  ex- 
clusively defined  by  the  peculiarities  of  its  basis-substance,  it  is  to  be 
understood  that  its  corpuscles,  though  varying  in  size,  shape,  and 
arrangement,  are  made  up  everywhere  simply  of  protoplasm,  or,  as 
in  dentine,  of  fibers  of  living  matter  alone. 

A.  Myxomatous,  or  31ucoid  Tissue,  is  the  earliest  formation  ia 
the  embryo,  and  all  varieties  of  connective  tissue  are  of  myxo- 
matous origin.  This  tissue  shows  fields  of  basis-substance  cor- 
responding in  size  and  shape  to  medullary  corpuscles,  or.  proto- 
plasmic bodies,  which  have  been  transformed  into  a  jelly-like 
mass,  though  their  minute  structure  has  remained  unchano-ed. 


48 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


The  reticular  myxomatous  tissue  is  composed  of  branching 
protoplasmic  bodies,  the  meshes  of  which  hold  a  gelatinous 
(myxomatous)  basis-substance  with  central  nuclei,  the  rem- 
nants of  previous  protoplasmic  bodies.  (See  Fig.  25.)  To  this 
type  belong  the  tissue  of  the  placenta,  the  umbilical  cord,  the 
lymph-ganglia,  the  so-called  adenoid  laj^ers  and  follicles  of  the 
mucous  membranes,  and  the  pulps  of  the  teeth.  Fat  is  a  variety 
of  myxomatous  tissue  held  as  a  basis-substance  in  a  protoplasmic 
net-work. 

Fig.  25. 


Reticular  Myxomatous  Tissue  of  a  Villus  op  the  Placenta  op  a  Human  Embryo, 
Four  Months  Old.    (From  C.  Heitzmann.) 

E,  E,  epithelial  cover  of  the  yillu?  ;  B,  solid  bud  of  a  growing  villus  ;   C,  C,  capillary  blood- 
vessels, overlapped  by  the  myxomatous  reticulum.    Magnified  500  diameters. 


B.  Fibrous,  or  Striated  Tissue,  derives  its  name  from  the  striated 
appearance  of  the  basis-substance,  which  upon  being  torn  asunder 
has  the  aspect  of  fibrillse.  The  bundles  of  such  fibers  may  be 
thin  and  arranged  loosely,  as  in  the  so-called  areolar  variety 
of  connective  tissue  (pia  mater,  arachnoid,  and  peritoneum),  or 
they  may  be  densely  put  together  and  traversed  by  large  branch- 
ing protoplasmic  bodies.     The  bundles  are  either  arranged  per- 


GENERAL    HISTOLOGY, 


49 


fectly  parallel,  as  we  observe  in  the  tendon  (see  Fig.  26),  or 
interlacino-  and  interwoven  in  all  directions,  as  we  find  them  in 


Fig.  26. 


Texdox  of  Achilles  of  a  Young  Person.    Loxgitudixal  Section.    Chromic  Acid 
Specisien.    (From  G.  Heitzmann.) 

B,  bundles  of  striated  connective  tissue,  here  and  there  finely  dotted;  TC,  tendon  cor- 
puscles within  the  bundles  or  between  the  smallest  bundles;  72',  interstitial  medullary  tissue 
carrying  capillary  blood-vessels,  C.    Magnified  500  diameters. 


the  derma  of  the  skin,  the  periosteum,  the  perichondrium,  the 
articular  and  the  interarticular  ligaments,  etc. 

C.  Cariilaginous,  or  Chondrogenous  Tissue,  is  composed  of  proto- 
plasmic bodies  imbedded  in  a  dense  and  tough  basis-substance. 
(See  Fig.  27.)  In  the  juvenile  condition  it  is  traversed  by 
medullary  spaces  containing  blood-vessels.  The  existence  of 
connections  between  the  protoplasmic  bodies,  as  well  as  of  the 
reticulum  in  the  basis-substance,  was  proven  by  the  method  of 
staining  with  a  solution  of  chloride  of  gold  and  treatment  with 
absolute  alcohol. 

There  are  three  varieties  of  this  tissue,  viz  : 
The  Hyaline  Cartilage. 
The  Fibrous  Cartilage. 
The  Reticular  Cartilage. 

D.  Bong  or  Osseous  Tissue. — Of  this  there  are  two  main  varie- 
ties, viz :  The  cancellous,  epiphyseal,  or  spongy,  and  the  compact, 
or  cortical,  bone-tissue. 

Cancellous  bone  is  the  first  bone  formed  in  the  embryo,  long 

5 


50 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


before  the  cortical  bone  makes  its  appearance.  (See  Fig.  28.) 
In  human  beings  it  is  the  only  variety  of  bone  present  up  to  the 
fifth,  sixth,  or  even  the  seventh  month  of  intrauterine  develop- 
ment. In  dogs,  cats,  and  rabbits,  at  birth,  none  but  cancellous 
bone  is  found  in  the  skeleton.  This  tissue  consists  of  small, 
interconnected  trabeculie  of  bone,  surrounding  and  inclosing 
spaces  of  medullary  or  myxomatous  tissue,  supplied  with  capil- 
lary blood-vessels.     The  trabeculse  are  faintly  lamellated,  and 

FiCx.  27. 


-M 


'>"^J 


^  <^-^  %i1  f "  '^^^iV  ^-^^V.  ■i^fjl  ir^iie 


Hyaltxe  Cartilage  from  the  Condyle  op  Femtje  or  a  Ne^lt-born  Pup.    Chromic 
Acid  Specijien.    (From  C.  Heitzmanx.) 

C,  the  tissue  of  the  hyaline    cartilage,  with  scattered  groups  of  cartilage-corpuscles;    lf» 
medullary  spaces,  containing  blood-vessels  and  medullary  tissue.    Magnified  100  diameters. 


hold  a  number  of  branching  protoplasmic  bodies,  the  bone-cor- 
puscles. The  latter  have  been  known  only  since  1870,  and  w^ere 
discovered  by  S.  Strieker.  Previous  to  that  date  dry  bones, 
ground  thin  and  mounted  in  Canada  balsam,  w^ere  resorted  to 
for  microscopical  examination.  In  such  specimens  only  the 
spaces  holding  the  protoplasmic  bodies  and  their  offshoots,  the 
so-called  canaliculi,  were  visible.  To-day  we  know  that  not  only 
each  lacuna  holds  a  bone-corpuscle,  but  that  every  canaliculus 


GENERAL    HISTOLOGY.  51 

contains  a  small  fiber  of  living  matter,  and  the  entire  basis-sub- 
stance is  traversed  by  an  extremely  delicate  net-work  of  such 
matter,  the  meshes  of  which  are  filled  with  a  ghie-yielding  basis- 
substance,  saturated  with  lime-salts. 

Cortical  hone-tissue  is  composed  of  parallel  lamellae,  bunched 
together  in  the  shape  of  so-called  Haversian  systems,  extending 
longitudinally  with  the  longitudinal  axis  of  the  bones.  (See 
Fig.  29.)     The  center  of  each  Haversian  system  is  occupied  by 

Fig.  28. 


Tibia  of  a  Newlt-borx  Pup.    Longitudinal  Section.    Chromic  Acid  Specimen. 
(From  C.  Heitzmann.) 

T,  trabecule  of  bone-tissue  containing  bone-corpuscles:  J/,  medullary  spaces  filled  with 
medullary  tissue,  holding  blood-vessels  in  the  most  central  portions.    Magnified  200  diameters. 

a  medullary  canal  that  holds,  besides  a  straight  capillary  blood- 
vessel, a  varying  amount  of  medullary  tissue.  The  older  the 
individual,  the  scantier  is  this  medullary  tissue.  The  lamellated 
region  contains  the  branching  bone-corpuscles,  the  same  as  the 
trabeculfe  of  cancellous  bone.  The  offshoots  of  these  corpuscles 
are  arranged  radiately,  interconnecting  not  only  all  protoplasmic 
bodies  within  the  bone,  but  also  the  medullary  corpuscles, 
and,  indirectly,  the  walls  of  the  blood-vessels.     This  is  an  im- 


52 


THE    ANATUMY    AND    rATHOLU(JY    OF    THE    TEETH. 


portant  fact,  since  it  explains  the  nutrition  of  the  compact  bone, 
which  is  sparingly  supplied  with  blood-vessels,  though  endowed 
with  properties  of  life.  Each  large  bone,  the  shaft-bones  as 
well  as  the  lower  maxilla,  contains  in  its  center  a  large  medul- 
lary space  traversed  by  cancellous  bone-structure.  In  youth 
the  medullary  spaces  hold  the  so-called  red  medulla,  while  in 
more  advanced  age  they  contain  fat-tissue.  Epiphyseal  ex- 
tremities of  bones  are  mainly  cancellous  and  covered  by  a  thin 
layer  of  cortical  structure,  while  articular  ends  are  directly 
coated  with  hyaline  cartilage. 


TnjiA  OF  A  Grown  Dog— Cortical  Portion,  Transverse  Section.    Chromic-Acid  Spe- 
cimen.   (From  C.  Heitzmann.) 

S,  Haversian  system  of  lamellje,  containing  the  bone- corpuscles,  C,  with  their  radiating  off- 
shoots; ilf,  central  medullary,  so-called  Haversian  canal,  containing  a  capillary  blood-vessel ; 
/,  interstitial  bone-tissue  indistinctly  lamellated.    Magnified  500  diameters. 


II.  Muscle -tissue  is  the  motor  apparatus  proper,  and  occurs 
in  two  varieties, — viz,  the  smooth  or  involuntary ,  and  the  striated 
or  vohmtari/  masele-tissae.  The  former  is  composed  of  spindle- 
shaped  protoplasmic  bodies,  often  holding  rod-like  nuclei  in 
their  interior.  The  contraction  of  these  spindles  results  in  a 
slow  movement  of  the  muscular  walls  of  the  cavities  of  the 
body,  and  the  larger  blood-vessels,  arteries,  and  veins. 

The  striated  or  voluntary  musdes  consist  of  large  spindle-shaped 
fibers,  in  which  there  are  disks  made  up   of   small  prismatic 


GENERAL    HISTOLOdY. 


53 


pieces,  the  so-CiTlled  "  sarcous  elements."  In  longitudinal  section 
the  disks  of  the  sarcous  elements  appear  in  great  regularity  of 
arrangement,  separated  from  one  another  by  a  slight  interstice 
tilled  with  a  liquid.    (See  Fig.  30.)    The  shape  and  arrangement 


Fig.  30. 


Muscle  op  Tongue  op  Max— Chromic-Acid  Specimen.    (From  C.  Heitzmann.) 

L,  longitudinal  musele-fiber,  broken  otf  and  exhibiting  its  structureless  sheath,  the  sarco- 
lemma,  S ;  N,  medullated  nerve-fiber,  terminating  in  the  motor  hi]],  H ;  T,  transverse  section 
of  a  muscle-fiber;  P,  the  perimysium,  holding  capillary  blood-vessels,  C,  and  nerves,  iV^. 
Magnified  500  diameters. 

of  the  sarcous  elements  greatly  vary,  depending  upon  the  posi- 
tion of  the  muscle-fiber  at  death.  "Whatever  the  configuration 
of  the  sarcous  elements  be,  they  are  invariably  interconnected 
by  extremely  delicate  conical  threads,  both  in  the  longitudinal 


54 


THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


and  transverse  directions.  The  sarcous  elements,  like  the 
spindles  of  the  involuntary  muscles,  are  formations  of  con- 
tractile or  living  matter.  The  structure  of  the  muscle-fiber  is, 
according  to  Heitzmann,  identical  with   that   of  protoplasm. 


Fig.  31. 


Branch  of  the  Motoe  Oculi  Nerve  of  Man.    (From  C.  Heitzmann.) 

L,  longitudinal,  T,  transverse  section  of  the  bundle  ;  PE,  external  perineurium;  PJ,  inter- 
nal perineurium;  ML,  myelin  investment;  A,  axis-cylinder;  M,  transverse  sections  of 
muscle-fibers.    Magnified  600  diameters. 


The  only  difference  is  that  in  protoplasm  the  granules  and  the 
points  of  intersection  of  the  minute  reticulum  are  small  and 
arranged  without  regularity;  whereas  in  the  striated  muscle 
the  points  of  intersection  are  large  and  of  a  prismatic  or  disk- 


GEXERAL    HISTOLOGY, 


55 


like  shape.  The  contraction  of  tlie  protoplasm  and  that  of  the 
muscle-fibers  are  based  upon  the  same  principle. 

III.  Nerve-tissue. — As  the  writer  intends  to  confine  himself 
to  but  a  brief  description  of  the  nerves,  he  will  not  dwell  upon 
the  central  nervous  organs,  the  brain  and  the  spinal  cord. 

"We  distinguish  two  varieties  of  nerve-fibers, — viz,  the  medid- 
lated  and  the  non-medullated. 

The  medidlated  nerre-fibers  exhibit  to  the  naked  eye  a  white 
color,  owing  to  the  presence  of  m>/elin,  or  nerve-fat,  which  sur- 
rounds the  central  conducting  fiber,  the  so-called  axis-cylinder. 
In  transverse  sections  of  bundles  of  meduUated  nerve-fibers  we 
observe  around  the  periphery  of  the  bundle  a  sheath  of  delicate 
fibrous  connective  tissue,  the  external  j^erineurium.     From   this 

Fig.  32. 


Medullated  and  Non-Medullated  Nerte-Fibers  from  the  Retina  of  a  Bull.   (From 

C.  Heitzmann.) 
S'^,  myelin  sheath,  with  oblong  nuclei  and  (S-)  transverse  septa.    The  myelin  oozed  out. 
JV,  non-medullated  nerve-fibers,  with  varicose  enlargements.    Magnified  600  diameters. 


layer  arise  minute  offshoots  which  encircle  each  nerve-fiber,  as 
\h.Q  internal  perineurium.  (See  Fig.  31.)  Next  follows  a  thin  laj'er 
of  nucleated  connective  tissue,  Schwann's  sheath.  After  this  a 
laj^er  of  myelin  or  nerve-fat,  which  surrounds  the  central  axis- 
<?ylinder.  The  latter  is  enveloped  by  an  extremely  thin,  flat 
laj'er  of  connective  tissue,  the  sheath  of  the  axis-cylinder.  The 
medullated  nerve-fibers,  upon  approaching  the  surface  of  the 
organ,  usually  lose  their  myelin-sheaths,  and  the  hitherto  undi- 
vided axis-cylinder  splits  up  into  minute  beaded  fibrill^e,  which 
directly  join  the  reticulum  of  the  protoplasmic  bodies  at  the 
periphery. 

The  non-medullated  nerve-fibers  are  mere  axis-cylinders,  lacking 
the   myelin   investment,  but,  as  a  rule,  inclosed  by  an  axis- 


56 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


cylinder  sheath.  (See  Fig.  32.)  At  the  periphery  they  split  .up 
into  axis-fibril] fB.  The  axis-cylinder  has  a  delicate  reticular 
structure,  and  the  axis-fibrill?e  are  linear  projections  of  the 
reticulum.  The  nerve  action,  probably,  is  based  upon  the  con- 
traction of  this  reticulum  of  living  matter.  If  the  contraction 
runs  centripetally,  it  is  termed  sensation  ;  if  centrifugally,  it 
leads,  when  connected  with  muscle-fibers,  to  motion. 

IV.  Epithelial   Tissue.— The   surface  of  the  body,— like   all 
cavities  which  are  in  direct  or  indirect  communication  with  the 

Fig.  33. 


Stratified  Epithelium  of  the  Skix,  covering  a  Myxofibroma  on  the  Right 
Shoulder.    Vertical  Section.    (From  C.  Heitzmann.) 

F,  flat  epithelia  :  Cu,  cuboidal  epithelia;  Co,  columnar  epithelia,  all  the  three  composing  the- 
epithelial  layer,  £■/  -D,  derma  of  skin,  composed  of  vascularized  connective  tissue,  C.  Magni- 
fied 600  diameters. 


outer  world, — is  covered  with  either  a  single  or  a  stratified  layer 
of  nucleated  protoplasmic  bodies,  the  epithelia.  These  forma- 
tions are  separated  from  one  another  by  a  thin  stratum  of  horny 
cement-substance,  chemically  different  from  the  glue  of  the 
basis-substance  of  connective  tissue.  The  cement-substance 
invariably  is  pierced  by  delicate  conical  offshoots  of  living 
matter,  Max  SchuUze's  thorns,  interconnecting  the  epitheUal 
elements.     The  closed  cavities  of  the  body,  including  those  of 


GENERAL    HISTOLOGY. 


57 


the  heart,  blood-vessels,  and  lymph-vessels,  are  lined  by  endo- 
thelia, — flat,  protoplasmic  bodies,  morphologically  identical  with 
epithelia. 

"We  distinguish  three  main  varieties  of  epithelia, — viz,  the  Hat, 
the  cuboklal,  and  the  eohimnar.  The  last  variety  often  carries  fine 
moving  hairs,  the  so-called  cilia.  A  single  layer  of  epithelium 
may  be  constituted  of  either  of  the  above-named  varieties. 
Stratified  epithelia,  such  as  we  find  on  the  surface  of  the  skin 
and  on  the  mucous  membrane  of  the  oral  cavity,  including  the 
gums,  are  made  up  of  three  varieties.     The  lowest  layer — that 

Tig.  34. 


Blood-Vesskls  from  the  Loose  Adventitial  Connective  Tissue  op  the  Spermatic 
Cord  of  Man.    (From  C.  Heitzmann.) 

A,  artery,  with  E.  endothelial  and  covering  hyaline  layer;  ,1/,  smooth  musclo  layer:  0< 
adventitial  layer  :  V,  vein,  exhibiting  the  same  layers  as  the  artery  :  C.  capillary  blood-vessels, 
composed  of  a  single  endothelial  layer,  with  a  surrounding  delicate  adventitial  fibrous  connec- 
tive tissue.    Magnified  200  diameters. 

nearest  the  connective  tissue — is  composed  of  a  single  row  of 
columnar  epithelia;  the  next,  of  a  number  of  caboidal  epithelia ; 
and  the  outermost,  of  a  number  of  flat  epithelia.  The  latter,  on 
the  surface  of  the  skin,  are  entirely  hornified,  whereas  on  the 
surface  of  the  oral  mucous  membrane  only  the  protoplasm  is 
hornified,  the  nucleus  being  still  endowed  with  properties  of  life. 
(See  Fig.  33.)  The  finest  terminations  of  the  sensory  nerves,  the 
axis-fibrill?e,  run  in  the  cement-substance  between  the  epithelia, 
and  there  inosculate  directly  with  the  thorns,  and  indirectly 
with  the  protoplasmic  reticulum,  thus  rendering  all  epithelia 
sensitive. 


58  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

Besides  protecting  the  surface  of  the  body,  the  epithelia  have 
to  perform  the  important  duty  of  secretion.  A  colony  of 
epitheha  is  termed  a  gland.  We  distinguish  two  varieties  of 
glands, — viz,  the  acinous  or  berry-shajjed,  and  the  tubular.  All  the 
mucous  and  salivary  glands  emptying  their  secretion  into  the 
oral  cavity  are  of  the  acinous  variety.  Quite  frequently,  but 
erroneously,  these  glands  are  termed  follicles,  a  name  that  applies 
to  an  aggregation  of  lymph-tissue,  and  this  latter,  being  a  forma- 
tion of  myxomatous  connective  tissue,  never  secretes. 

All  blood-vessels  are  lined  by  flat  endothelia.  The  wall  of  a 
capillary  is  made  up  of  endothelia  only.  The  arteries  have, 
besides  the  endothelia,  a  more  or  less  heavy  middle  coat  of 
smooth  muscles,  and  an  outer  coat,  the  so-called  adventitia,  com- 
posed of  fibrous  connective  tissue.  The  veins,  in  structure, 
resemble  the  arteries,  but  have  a  much  less  pronounced  muscular 
€oat.     (See  Fig.  34.) 

The  lymph-vessels  are  made  up  of  a  single  layer  of  endothelia, 
whereas  the  larger  lymphatics  have  a  middle  muscular  coat  and 
an  outer  adventitial  one. 


CHAPTER  IX. 

DEVELOPMENT    OF.  CONNECTIVE  TISSUE. 

To  the  minds  of  Schleiden  (1837)  and  Theodore  Schwann 
(1839)  the  vegetable  and  animal  organisms  were  composed  of 
cells  and  their  derivations, — viz,  intercellular  substance.  The  cell 
was  considered  to  be  an  individual,  and  composed  of  a  vesicle 
with  liquid  or  semi-liquid  contents,  and  a  central  nucleus.  An 
organism,  it  was  thought,  was  built  up  of  millions  of  such  cells. 
Each  cell  might  originate  spontaneously  from  an  albuminous 
liquid  by  the  formation  of,  first,  the  nucleus,  and  afterward  the 
cell-wall,  similar  in  shape  to  two  watch-glasses  held  together,  and 
lastly  an  accumulation  of  liquid  within  the  vesicle,  the  cell-wall. 

Schwann's  views,  adopted  by  the  Vienna  school,  guided  by 
Kokitansk}',  were  overthrown  in  1852  by  Rudolph  Virchow,* 
who  stated  that  a  cell  was  provided  with  a  wall  of  its  own,  held 
a  viscid  albuminous  liquid,  and  was  itself  the  seat  of  life,  which 
it  was  not  considered  to  be  by  Schwann  nor  the  Vienna  school. 

*  "Die  Cellularpathologie."     Berlin,  1871. 


DEVELOPMENT    OF    COXXECTIVE    TISSUE. 


59 


Virchowheld  and  still  holds  the  view  that  the  organism  is  com- 
posed of  a  large  number  of  individual  cells,  separated  from  one 
another  by  an  intercellular  substance,  which  he  considers  to  be 
a  product  of  secretion  on  the  part  of  the  cell.  He,  however, 
acknowledged  one  variety  of  interconnected  cells,  termed  star- 


FiG.   35. 


B 


DiAORAM  OF   THE  STRUCTURE   OF    CoXXECTITE   TiSSUE,   ACCORDING  TO   R.   ViRCHOW    (1852). 

A,  structure  and  development  of  reticular  car?i7af?e.—  T.  territory  of  the  cell,  called  inter- 
cellular substance,  considered  inert  and  a  product  of  secretion  of  the  cell.  JZ ^  structure  and 
development  of  fibrous  connective  tissue. — C,  nucleated  cell,  lying  in  a  cavity;  F,  fibers 
around  the  cell,  considered  inert  glue  and  a  product  of  secretion  of  the  cells. 

shaped  or  stellate,  such  as  we  know  to  exist  in  the  myxomatous 
tissue.     (See  Fig.  35.) 

In  1861,  Max  Schultze,"^  of  Bonn,  Germany,  announced  novel 
views  in  regard  to  the  construction  of  cells.  He  denied  the 
existence  of  a  cell-wall,  and  said  that  a  cell  is  a  lump  of  proto- 
plasm holding  granules  and  a  nucleus,  endowed  with  the  prop- 
■erties  of  life.     The  word  "  protoplasm"  was  accepted  by  him 


*  MuUer' s  Archil-    1861. 


60 


THE  ANATO.A[Y  AND  PATHOLOGY  OF  THE  TEETH. 


from  the  botanist,  Hugo  von  Molil,  who,  several  years  before, 
had  applied  this  term  to  the  contents  of  vegetable  cells.  In 
England,  L.  S.  Beale*  almost  simultaneously  announced  similar 
views,  applying  the  term  "  bioplasma"  to  the  substance  which 
builds  up  the  cells.     This  bioplasma  was  the  true  living  or  ger- 

FiG.  36. 


Diagram  of  the  Structure  of  Connective  Tissue,  according  to  Max  Schultze  (1861). 

A,  structure  and  development  of  reticular  cartilage. — a,  territory  originally  composed  of  a 
number  of  embryonal  corpuscles, — protoplasm:  6,  peripheral  protoplasmic  bodies  transformed 
into  inert  glue-yielding  basis-substance,  the  central  protoplasmic  body  left  unchanged, — carti- 
lage-cell; c,  fully-developed  territory.  B,  structure  and  development  of  fibrous  connective 
tissue. — a,  elongated  protoplasmic  bodies  around  the  central  cell ;  b,  fibrous  basis-substance,  the 
product  of  a  chemical  transformation  of  protoplasm  ;  c,  unchanged  granular  and  nucleated 
protoplasm,  the  connective-tissue  cell. 


minal  matter,  whereas  all  intercellular  substances  he  considered 
as  inert  or  formed  material.  Unfortunately,  he  was  led  to  term 
the  muscles  and  nerves  "  formed  material"  also,  and  yet  these 
tissues  are  known  to  be  the  most  active  of  the  organism.     It  is 

*  "  On  the  Structure  and  Growth  of  the  Tissues."'    London,  1865. 


DEVELOPMENT    OF    COXNECTIVE    TISSVE.  61 

for  this  reason  that  Beale's  views  have  attracted  but  little  atten- 
tion. 

Max  Schultze's  assertions  did  not  directly  affect  the  cell-doc- 
trine, although  he  admitted  that  the  term  "  cell"  had  lost  its 
significance,  and  that  it  should  be  applied  only  in  honor  of  its 
discoverers,  Schleiden  and  Schwann.  M.  Schultze  at  the  same 
time  propounded,  concerning  the  origin  of  the  intercellular 
substance,  new  views  which  must  be  understood  in  order  to 
trace  the  development  of  the  modern  researches  in  the  process 
of  inflammation.  In  the  opinion  of  Virchow,  intercehular  sub- 
stances were  merely  a  secretory  product  of  the  cells,  whereas 
Max  Schultze  proved  that  these  substances  are  derivations  of 
protoplasm.  According  to  Schultze,  a  number  of  protoplasmic 
bodies  become  chemically  transformed  into  basis-substance,  and 
thus  they  are  rendered  inert  and  dead.  (See  Fig.  36.)  Beale's 
doctrine  was  different,  since  he  said  that  an  originally  large  mass 
of  bioplasma  is  converted  at  the  periphery  into  formed  material, 
and  only  the  central  portion  remains,  as  forming  or  germinal 
matter. 

Soon  afterward,  E.  Briicke,  of  Vienna,  asserted  that  neither 
were  the  granules  nor  was  the  nucleus  an  essential  feature  of  a 
cell,  and  consequently  he  defined  the  cell  as  a  structureless  lump 
of  protoplasm,  intrinsically  destitute  of  granules  and  a  nucleus. 
The  expression  "  structureless"  indicated  not  necessarily  that  a 
structure  was  absent,  but  that  it  could  not  be  made  out  with  the 
microscope.  He  likewise  admitted  that  a  lump  of  protoplasm 
is  the  real  seat  of  life,  and  is  able  to  produce  new  lumps — i.e., 
new  cells — by  proliferation  and  division,  in  normal  development 
of  the  tissues  as  well  as  in  morbid  processes. 

In  1873,  Carl  Heitzmann,  at  that  time  in  Vienna,  published  a 
series  of  articles  in  the  Vienna  Academy  of  Sciences,*  exploit- 
ing yet  further  entirely  novel  discoveries  concerning  the  struc- 
ture of  protoplasm,  and  the  structure  and  origin  of  the  basis- 
substance. 

Heitzmann  maintains  that  a  cell,  or  a  lump  of  protoplasm, 
hitherto  considered  structureless,  is  indeed  possessed  of  a  pro- 
nounced reticular  structure.  Since  he  had  seen  this  reticulum 
in  continuous  change  of  place  and  shape  during  the  locomotions 
of  living  protoplasmic  lumps,  such  as  amoebae,  colorless  blood- 
corpuscles,  etc.,  he  called  the  substance  which  builds  up  the 

''^ Sitzuncfsherlchte  der  Wiener  Akademie  der  Wissenschoffen,  1873 


62 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


reticulum  the  living  or  tlie  "  contractile  matter"  proper.  He 
designates  as  formations  of  living  matter  the  nucleus,  the  gran- 
ules, with  their  interconnecting  threads,  and  an  extremely  thin 
layer,  inclosing  the  lump  of  protoplasm  all  around.  At  first  the 
existence  of  the  reticulum  was  denied  by  most  observers,  and 

FiC4.  37. 


Diagram  of  the  Structure  op  Connective  Tissue,  according  to  C.  Heitzmann  (1873). 

A,  structure  and  deveIox>ment  of  reticular  cartilage. — «,  territory  originally  composed  of  a 
number  of  embryonal  corpuscles,— protoplasm  containing  a  reticulum  of  living  matter;  &,  peri- 
pheral protoplasmic  bodies  in  the  beginning  inflliration  with  glue-yielding  basis-substance,  the 
chemical  change  taking  place  in  the  fluid,  filling  the  meshes  of  the  reticulum  ;  the  central  pro 
toplasmic  body  left  unchanged, — cartilage-corpuscle;  c,  infiltration  with  basis-substance  further 
advanced  ;  d,  infiltration  with  basis-substance  accomplished,  the  reticulum  present,  but  ren- 
dered invisible.  B,  structure  and  development  of  fibrous  connective  tissue. — a,  branching  and 
interconnecting  protoplasmic  tracts;  6,  fibers  composed  of  protoplasmic  spindles,  holding  the 
reticulum  of  living  matter,  all  interconnected  by  living  matter;  c,  advanced  infiltration  with 
basis-substance,  the  reticulum  present,  but  rendered  invisible. 

afterward,  when  they  could  not  any  longer  deny  it,  they  said  that 
it  was  not  originally  observed  by  Heitzmann,  but  was  discovered 
by  C.  Frommann  in  1867.  Frommann,  it  is  true,  speaks  of  a 
reticulum  in  connective  tissue,  and  in  ganglionic  cells,  but  with- 


DEVELOPMENT    OF    COXXECTIYE    TISSUE.  63 

out  giving  an  illustration  thereof.  He  afterward  declared  that 
he  had  never  used  lenses  of  a  higher  power  than  450  diameters. 
To  observe  the  reticulum  in  the  protoplasm  with  such  a  power 
of  the  microscope  is  simply  impossible,  even  to  an  experienced 
eye.  Indeed,  from  800  to  1000  diameters  are  required  for  the 
study  of  the  reticulum  under  consideration.  That  the  reticulum 
exists  is  to-day  a  settled  fact,  the  more  so  as  Strieker,  in  1890, 
succeeded  in  reproducing  it  by  photography,  magnifying  a  livino- 
colorless  blood-corpuscle  of  the  proteus  by  means  of  the  electric 
microscope,  with  a  power  of  2500  diameters.*  In  this  photo- 
micrograph the  reticulum  in  the  protoplasm  is  exactly  the  same 
as  discovered  and  described  by  Carl  Heitzmann  in  1873. 

That  the  nucleus  is  made  up  of  living  matter  became  appar- 
ently doubtful  when,  in  1875,  the  so-called  karyokinesis  of  the 
nucleus  was  discovered  by  Strassburger,Biitschli,  Flemming,  and 
others.  It  was  shown  that  the  nucleus  is  composed  of  loop-like 
threads  representing  stars  and  double-stars  preceding  its  divi- 
sion. Since  these  loops  could  be  stained  deeper  by  certain  anilin 
dyes,  especially  safranin,  than  the  granules  of  the  protoplasm, 
it  was  asserted  that  the  nucleus  is  composed  of  a  substance 
of  its  own,  called  "  nuclein"  and  "chromatin."  It  is  plain 
that  a  substance  capable  of  changing  its  shape  and  place  must 
be  living  matter.  The  karyokinetic  threads  assumed  a  deeper 
color  only  on  account  of  their  being  more  bulky  than  the  rest 
of  the  reticulum  in  the  surrounding  protoplasm.  Besides,  it 
was  shown  that  even  at  the  height  of  karyokinesis,  the  loops 
remain  interconnected  with  the  surrounding  reticulum  of  the 
protoplasm,  which  again  proves  their  identity,  ^ot  only  do  all 
movements  occur  in  consequence  of  contraction  and  extension 
of  the  reticulum,  but  all  new  formations  and  outgrowths  start 
from  this  substance,  respectively  from  the  granules,  the  points  of 
intersection  of  the  reticulum.  This  again  proves  that  the  reti- 
culumis  the  living  matter  proper,  in  the  meshes  of  which  there 
exists  a  liquid  holding  nitrogen,  but,  being  a  liquid,  not  endowed 
with  the  properties  of  life. 

Originally  every  so-called  cell  is  a  solid  granule  of  living 
matter,  which  in  turn  becomes  vacuoled  by  an  accumulation  of 
liquid,  and,  at  last,  is  reticulated,  in  consequence  of  perforations 
of  the  walls  of  the  vacuoles. 

Another  discovery  of  Carl  Heitzmann,  in  1873,  was  that  the 

*  Arbeiten  aits  dem  Institute  fur  experimentelle  Pathologie.   1890. 


64  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

intercellular  or  basis-substance  of  tlie  connective  tissue  is  not 
dead  or  inert,  as  hitherto  supposed,  but  is  alive  in  the  same  sense 
as  the  cells  themselves.  The  reticulum  of  living  matter  visible 
in  the  latter  is  present  also  in  the  basis-substance,  though  ren- 
dered invisible  by  chemical  changes  and  a  solidification  of  the 
originallv  liquid  contents  of  the  meshes  in  the  protoplasm.  It 
has  been  proven  that  in  all  varieties  of  connective  tissue,  in  the 
muscles,  the  nerves,  and  the  epithelia,  the  so-called  cells  are 
interconnected  by  means  of  delicate  threads  of  living  matter,  or 
indirectly  by  the  reticulum  pervading  the  basis-substance.  (See 
Fig.  37.) 

In  the  development  of  all  varieties  of  basis-substance,  the 
protoplasm  shares,  by  a  process  of  chemical  transformation  which" 
renders  it  more  or  less  firm  and  solid.  It  has  also  been  proven 
that  in  the  formation  of  basis-substance  the  protoplasm  does 
not  perish  altogether,  but  only  the  lifeless  liquid  portion  which 
is  held  in  the  meshes  of  the  reticulum  becomes  solidified,  whereas 
the  reticulum  itself  remains  unchanged. 

Development  of  Bone-Tissue. — While  all  varieties  of  connec- 
tive tissue  develop  directly  from  indifferent  or  medullary  tissue, 
bone  is  a  secondary  formation,  originating  either  from  previous 
hyaline  cartilage  or  from  fibrous  connective  tissue.  The  latter 
is  the  case  with  the  fiat  bones  of  the  skull ;  the  former,  with  all 
the  rest  of  the  skeleton,  including  the  lower  jaw  and  the  greater 
portion  of  the  upper  jaw.  In  both  instances  the  process  is 
identical ;  indeed,  W.  X.  Sudduth*  has  shown  that  even  the  lower 
jaw  may,  in  part,  develop  from  fibrous  connective  tissue,  inde- 
pendently of  hyaline  cartilage.  AYhenever  hj^aline  cartilage  is 
about  to  be  transformed  into  bone-tissue,  as  in  the  case  of  the 
lower  jaw  in  the  sixth  week  of  embryonal  life,  the  cartilage 
becomes  reduced  to  medullary  tissue,  a  process  frequently, 
though  not  always,  preceded  by  a  deposition  of  lime-salts  at  the 
border  of  the  territories  of  the  cartilage-corpuscles.  Sometimes, 
before  the  cartilage  begins  to  change  into  embryonal  tissue,  a 
calcified  frame  of  basis-substance  is  produced.  In  former  years, 
histologists  encountered  great  difficulties  in  explaining  the 
origin  of  the  medullarv  tissue.  Some  of  them — A.  Rollet,  for 
example — have  gone  so  far  as  to  assert  that  the  cartilage-cells 
perish  altogether,  and  that  into  their  places  colorless  blood-cor- 
puscles migrate,  giving  rise  to  bone-tissue.     To-day  all  such 

*"The  American  Svstem  of  Dentistry, "  1886. 


DEVELOPMENT    OF    CONNECTIVE    TISSUE.  65 

difficulties  have  vanished,  since  we  know  that  not  only  are  the 
cartilage-corpuscles  traversed  bj  a  net-work  of  living  matter, 
but  that  so  also  is  the  dense  basis-substance.  Nothing  is  required 
but  a  liquefaction  of  this  basis-substance  to  liberate  the  reticu- 

FiG.  38. 


^  -J'  ^i  \S\  'k^ 


^■ 


Humerus  of  a  Human  Embryo,  Five  Moxths  Old.    Sagittal  Sectiox.    Chromic  Acid 
Specimen-.    (From  C.  Heitzmanx.) 

C,  rows  of  cartilag-e-corpuscles  in  elongated  groups,  due  to  their  territories  :  F,  frame  of  calci- 
fied basis-substance,  around  which,  in  the  lower  portions,  the  first  traces  of  bone-tissue  are 
noticeable;  J/,  medullary  space,  containing  medullary  corpuscles.    Magnified  300  diameters. 

lum,  whereupon  the  protoplasmic  condition  of  the  tissue  is  re- 
established. The  newly-appearing  medullary  corpuscles,  in  this 
view,  are  nothing  but  the  result  of  the  return  to  the  embryonic 
condition  of  the  cartilage-tissue.    (See  Fig.  38.) ,  This  process  is 

6 


66 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


followed  by  an  outgrowth  of  living  matter  into  threads,  which 
afterward,  by  vacuolation,  become  hollowed,  and  thus  blood- 
vessels are  formed  holding  red  blood-corpuscles,  even  before 
union  with  the  already  permeable  capillary  system.  The  spaces 
filled  with  embryonal  or  medullary  tissue  are  bordered  by  the 
calcified  basis-substance  of  the  previous  cartilage,  this  evidently 
serving  as  a  support  of  the  cartilage,  which,  to  a  considerable 
degree,  has  been  reduced  into  protoplasm.     Around  this  calcified 

Fig.  39. 


Vertebra  of  a  Human   Embyro,  Five   Months   OLd.     Horizontal  Section.   Chromic 
Acid  Specimen.    (From  C.  Heitzmann.) 

M,  medullary  space,  with  central  blood-vessels  and  medullary  tissue  ;  B,  first-formed  globular 
territories,  containing  one  or  two  central  bone-corpuscles,  with  radiating  ofishoots.  The  terri- 
tories lie  against  the  trabeeulte  of  the  original  calcified  basis-substance  of  the  cartilage,  F. 
Magnified  500  diameters. 


frame  the  first-formed  territories  of  bone-tissue  are  seen,  with 
their  convexities  lying  against  the  calcified  basis-substance.  (See 
Fig.  39.)  Later  a  number  of  such  medullary  corpuscles  unite, 
coalescing  into  globular  masses  of  so-called  nu/eloplaxes  (Robin), 
or  giant  cells  (Yirchow),  in  which  we  frequently  notice  a  large 
number  of  nuclei  placed  at  nearly  regular  intervals.  (See  Fig. 
40.) 

Such  a  globular  bod}^  is  the  beginning  formation  of  a  territory 


DEVELOPMENT    OF    CONNECTIVE    TISSUE, 


67 


of  future  bone-tissue.  In  the  center  of  the  territory  a  certain 
amount  of  protoplasm  remains  unchanged,  representing  the 
future  bone-corpuscle,  whereas  the  peripheral  portion  of  the 
territory  becomes  infiltrated,  first  with  a  glue-yielding  basis- 
substance,  and  afterward  with  lime-salts.  The  latter  portion  is 
traversed  by  radiate  protoplasmic  oftshoots,  all  of  which  com- 
municate with  the  central  bone-corpuscle.  The  formations 
formerly  termed  lacriue^  therefore,  are  nothing  but  the  central 

Fig.  40. 


Surface  OF  THE  sciPULA  OF  ilv  TTE\     Chp  mic  \cid  ;?pecimen     (From  C.  Heitzmaxx.) 
C,  lamellated  bone,  with  bone-eorpuscles  ;  G,  a  single  territory  of  bone-tissue  liquefied,  result- 
ing in  the  formation  of  a  multinuelear  plastid  or  cell ;  M,  coalesced  masses  of  multinuclear 
plastids  or  cells.    Magnified  600  diameters. 


cavities  in  the  basis-substance,  holding  the  bone-corpuscle. 
What  have  been  termed  canalicuU  are  the  offshoots  of  the  central 
cavities,  holding  threads  of  living  matter.  In  fully-developed 
bone,  the  bone-corpuscles  and  their  offshoots  are  quite  conspicu- 
ous. By  decalcifiication  and  staining  there  is  rendered  visible 
throughout  the  whole  territory  a  delicate  reticulum  of  living 
matter,  identical  with  that  seen  in  the  protoplasm  itself 

LameUaffd  bone  arises  by  an  arrangement  in  rows  of  medullary 


08 


THE    AXATOMY    AND    l'ATH0L0(4Y    OF    THE    TEETH. 


corpuscles  adjacent  to  the  already  formed  bone.  The  large 
medullary  bodies  termed  osteoblasts  are  a  preceding  stage  of  bone, 
just  as  the  odontoblasts  are  of  dentine,  and  the  ameloblasts  are  of 
enamel.     Either  of  these  bodies,  which  resemble  epithelia,  must 


Fig.  41. 


Skull   of    Hvman    Embryo,  Four  Moxths  Old.    Horizontal  Section.    Chromic  Acid 
Specimex.    (From  C.  Heitzmanx.) 

F,  fibrous  connective  tissue  of  the  pericranium :  M,  medullary  space,  with  central  blood- 
vessel :  B,  first-formed  trabecula  of  bone :  0.  row  of  osteoblasts ;  C,  medullary  corpuscles  of 
the  inner  pericranium,  infiltrated  with  lime-salts.    Magnified  500  diameters. 


break  up  into  indifferent  corpuscles  in  order  to  give  rise  to 
permanent  bone,  dentine,  or  enamel. 

Whenever  bone  develops  from  fibrous  connective  tissue,  the 
latter  is  first  reduced  to  embryonal  tissue  in  the  same  manner  as 


THE    .MINUTE    STRUCTURE    OF    DENTINE.  69 

hyaline  cartilage  previous  to  the  formation  of  bone.  The  far- 
ther stages  of  the  production  of  bone  from  fibrous  tissue  are 
identical  with  those  in  the  development  from  hyaline  cartilage. 
(See  Fig.  41.) 

The  law  here  laid  down  is  but  a  brief  sketch  of  the  history 
of  development  as  first  established  in  1873  by  Carl  Heitzmann. 
Every  tissue  originates  from  protoplasm  in  the  state  of  indiffer- 
ence,— the  so-called  embrijonaL  or  iiiedullar;j  tissue.  No  tissue  can 
be  transformed  into  another  unless  it  has  first  been  reduced  to  the  em- 
bryonal condition.  This  law  holds  good  not  only  in  the  pro- 
gressive evolution  of  the  tissues,  but  also  in  their  retrogressive 
changes,  and  in  all  morbid  processes, — i.e.,  in  inflammation  or 
in  the  formation  of  new  tissue,  as  the  result  of  an  inflammatory 
process  termed  "  hyperplasia,""  or  in  the  formation  of  tumors. 


CHAPTER  X. 

THE  MINUTE  STRUCTURE  OF  DENTINE.* 

Methods. — The  best  method  in  the  preparation  of  bone-tissue 
for  microscopical  purposes  is  doubtless  the  treatment  with 
chromic-acid  solution  of  the  strength  of  from  one-half  to  one 
per  cent.  The  same  treatment  has  repeatedly  been  resorted  to  by 
different  investigators  of  tooth-substance.  The  writer  has  used 
this  solution  extensively  for  this  purpose,  adopting  precautions 
suggested  by  his  experience  in  dealing  with  bone.  These  are, 
to  immerse  only  a  few  teeth  in  a  large  vessel  containing  a  consid- 
erable amount  of  chromic-acid  solution  ;  to  renew  the  supply  of 
this  every  third  or  fourth  day,  and  to  add,  to  enforce  the  action 
of  the  fluid,  very  small  quantities  of  dilute  hydrochloric  acid. 
Under  this  treatment  the  teeth,  after  a  few  months,  become 
dark  green  from  the  reduction  of  the  chromic  acid  to  the  sesqui- 
oxide  of  chromium.  This  method  is  most  effective  for  softening 
teeth,  both  human  and  animal,  when  they  are  still  in  the  jaw. 
Wonderful  results  can  be  obtained  by  cutting  at  the  same  time 
bone   and   tooth  prepared  in  this  process;    also  in  preparing 

*--The  Distribution  of  Living  Matter  in  Human  Dentine,  Cement,  and 
Enamel."     Dental  Cosmos,  1878-1879. 


70  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

specimens  from  embryos,  in  order  to  stuclj"  the  history  of 
development  of  teeth.  This  method  is  highly  recommended, 
although  the  chromic  acid  only  softens  the  cement  and  dentine 
to  a  certain  depth,  so  that  a  tooth  kept  howsoever  long  in  the 
chromic-acid  solution  never  is  fit  to  be  cut  throuo;h  its  whole 
substance  at  one  time. 

The  sections  so  obtained  are  ready  for  staining  wdth  carmin 
or  hpematoxylin  after  they  have  been  immersed  in  and  washed 
with  distilled  water,  also  for  staining  with  chloride  of  gold, 
which  latter  may  be  done  in  the  following  wa}-  :  Thin  sections, 
after  having  been  washed  in  distilled  water  for  twenty-four  hours 
and  thus  freed  from  the  remnants  of  chromic  acid,  are  to  be 
placed  in  a  solution  of  chloride  of  gold  of  the  strength  of  half 
of  one  per  cent.,  by  means  of  glass  rods,  as  metals  must  be 
avoided  in  the  treatment  with  chloride  of  gold.  These  sections 
are  to  remain  in  the  solution  for  from  half  an  hour  to  an  hour, 
and  must  then  be  thoroughly  washed  with  distilled  water  and 
exposed  to  daylight  for  several  days,  when  they  are  ready  for 
mounting  in  the  ordinary'  way  in  chemically-pure  glycerin. 

The  greatest  objection  to  the  chromic-acid  treatment  is  that 
enamel  never  can  be  obtained  in  connection  with  the  dentine. 
If  hydrochloric  acid  has  been  used  in  addition  to  the  chromic- 
acid  solution,  the  enamel  is  almost  completely  dissolved.  If 
chromic  acid  alone  has  been  used,  the  enamel  becomes  so  brittle 
that  it  crumbles  into  small  particles  under  the  knife.  Under 
such  circumstances  the  outer  surface  of  the  dentine  looks  bay- 
like, owing  to  the  curved  lines  on  the  boundary  between  the 
dentine  and  enamel. 

Lactic  acid,  if  diluted  sufiiciently,  so  acts  upon  teeth  as  to 
dissolve  the  lime-salts  much  faster  than  chromic  acid  does. 
Specimens  prepared  in  this  waj',  however,  in  the  writer's  expe- 
rience, are  not  distinct  enough  for  study  with  high  powers  ;  hence 
a  tooth,  after  being  softened  with  lactic  acid,  has  to  be  immersed 
in  chromic-acid  solution  for  several  weeks.  But  the  o-reatest 
objection  to  the  use  of  the  lactic-acid  solution  is  the  formation 
of  mildew  in  a  relatively  short  time,  and  the  dissolving  of  the 
enamel  from  the  teeth. 

The  only  method  which  has  enabled  the  writer  to  obtain  speci- 
mens of  teeth  provided  with  all  hard  tissues  is  the  following:  A 
fresh  tooth,  or  one  kept  a  short  time  in  chromic-acid  solution,  is 
sliced  under  water  by  a  watch-spring  saw,  and  ground  as  thin  as 


THE    MINUTE    STRUCTURE    OF    DENTINE.  71 

possible  upon  a  corundum-wheel  of  a  lathe,  always  being  kept 
under  water.  The  lamella  thus  obtained  should  be  placed  in  a 
large  quantity  of  chromic-acid  solution  of  the  strength  of  half 
of  one  per  cent,  for  one  or  two  days,  with  the  view  of  harden- 
ing the  soft  parts  of  the  tooth  and  dissolving  the  lime-salts. 
After  this  the  specimen  may  be  stained  with  carmin,  hfema- 
toxylin,  chloride  of  gold,  etc.,  as  above  described,  and  mounted 
in  glycerin. 

The  saturated  solution  of  picric  acid  in  water  may  also  be 
used  for  the  decalcification  of  a  ground  slice  of  a  tooth,  though 
the  precipitated  acid  must  be  afterward  removed,  either  by  a 
brush  or  the  blade  of  a  knife.  Very  handsome  specimens  can 
be  obtained  by  staining  them  with  carmin  after  the  treatment 
with  picric  acid. 

Examination. — We  know  that  the  basis-substance  or  matrix 
of  the  dentine  is  analogous  to  that  of  bone, — i.e.,  that  it  is  glue- 
yielding,  and  at  the  same  time  infiltrated  with  lime-salts.  We 
learned  from  the  researches  of  E.  Neumann  that  the  basis-sub- 
stance is  denser  at  the  walls  of  the  canaliculi,  and  more  resistant 
to  the  action  of  strong  acids,  which  cause  the  appearance  of  a 
sheath  around  each  canaliculus  after  the  solution  of  the  inter- 
mediate substance  of  the  matrix  between  the  tubuli.  Analogous 
relations  also  exist  in  bone-tissue,  in  which  the  basis-substance 
is  decidedly  denser  on  the  walls  of  the  lacunae  and  Haversian 
canals. 

With  low  powers  we  cannot  see  in  the  dentine  anything  more 
minute  than  the  dentinal  canaliculi.  These  run  in  curved  sig- 
moidal  lines  from  the  boundary  of  the  pulp-cavity  to  the  per- 
iphery of  the  dentine ;  they  are  directed  obliquely  upward  in  the 
crown,  and  assume  a  more  horizontal  direction  in  the  region 
of  the  neck,  while  in  the  root  they  remain  horizontal  or  some- 
times turn  downward  to  a  varying  extent.  Besides  the  main  sig- 
moidal  curvature,  each  individual  canaliculus  exhibits  a  more  or 
less  wavy  course  in  its  way  through  the  dentine,  and  the  individ- 
ual curvatures  are,  as  a  rule,  very  marked  on  the  outer  periph- 
ery of  the  dentine. 

The  dentinal  canaliculi  reach  the  outer  surface  of  the  dentine 
only  on  the  circumference  covered  by  enamel.  On  the  periph- 
ery coated  by  cementum,  including  also  the  neck,  the  canaliculi 
terminate  b'^.fore  reaching  the  cementum,  and  are  replaced  by  a 
finely-granular  basis-substance  greatly  varying  in  width. 


72  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

The  distribution  of  the  dentinal  canaliculi  is  in  the  great 
majority  of  teeth  uniform  throughout  the  dentine,  although  ex- 
ceptionally the  writer  has  met  with  specimens  of  dentine  in  which 
there  were  smaller  or  larger  territories  devoid  of  dentinal  canali- 
culi ;  which  latter  looked  as  if  arranged  in  bundles  or  groups 
within  the  basis-substance.  This  relation  is  especially  visible  on 
transverse  sections  of  the  dentine.  An  irregular  arrangement 
of  the  dentinal  canaliculi  is  more  common  in  the  roots  than  in 
the  crowns. 

Each  canaliculus  contains  a  dentinal  fiber.  These  fibers, 
when  viewed  with  a  power  of  500  on  good  chromic-acid  speci- 
mens, exhibit  a  pale-gray  color,  and  run  without  ramification 
through  the  middle  of  the  canaliculi  up  to  the  outer  surface  of 
the  dentine.  The  outlines  of  these  fibers  alwa^'s  look  beaded 
and  fringed.  On  specimens  treated  with  chloride  of  gold,  the 
fibers  and  their  delicate  offshoots  show  a  distinct  violet  color, 
characteristic  of  living  matter  within  protoplasmic  formations, 
while  the  space  between  the  fiber  and  the  wall  of  the  canaliculus 
remains  unstained,  and  the  basis-substance  between  the  tubuli 
only  assumes  a  slight  violet  tinge. 

Longitudinal  sections  of  dentine,  stained  with  carmin  or 
chloride  of  gold,  if  examined  with  high  powers, — from  1000  to 
1500  diameters  (immersion  lenses), — exhibit  the  following : 

The  canaliculi  of  the  dentine  run  in  a  more  or  less  wavy 
course  through  the  basis-substance,  and  are,  as  a  rule,  bifur- 
cated only  at  the  periphery  of  the  dentine,  both  toward  enamel 
and  cementum.  Each  canaliculus  contains  a  central,  slightly 
beaded  fiber,  which  on  its  whole  periphery  sends  delicate  thorn- 
like elongations  through  the  light  space  between  the  central 
fiber  and  the  wall  of  the  canaliculus.  The  thorns  are  distinctly 
conical,  their  bases  being  attached  to  the  dentinal  fibers,  and 
their  points  directed  toward  the  basis-substance.  The  smallest 
thorns  spring  in  an  almost  vertical  direction  from  the  dentinal 
fiber,  while  somewhat  larger  ofishoots  may  run  obliquely  through 
the  basis-substance,  and  directly  unite  neighboring  fibers  with 
one  another  in  the  vicinity  of  the  enamel  and  cementum. 

The  basis-substance  shows  a  distinct  net-like  structure.  The 
light  spaces  surrounding  the  dentinal  fibers  send  delicate  elonga- 
tions into  the  basis-substance,  in  which,  through  repeated  branch- 
ing, a  light  net-work  is  established,  the  meshes  of  which  contain 
the   decalcified  glue-yielding  basis-substance.     The   finest  off- 


THE    MINUTE    STRUCTURE    OF    DEXTIXE. 


73 


shoots  of  the  dentinal  fibers  can  be  traced  only  mto  the  months 
of  the  elongations  of  the  canaliculi ;  on  the  periphery  of  the 
latter,  owing  to  their  great  delicacy,  the  offshoots  are  lost  to 
sight.  Coarser  offshoots  of  the  dentinal  fibers,  at  the  localities 
mentioned  before,  traverse  the  basis-snbstance  within  its  light 
net-work,  at  the  same  time  uniting  dentinal  fibers  directly,  and 
sending  slender  conical  offshoots  into  the  light  net-work  of  the 
basis-substance.     (See  Fig.  42.) 

The  dentinal  fibers  are  either  in  direct  connection  with  coarser 


ri' 


Fig.  42. 


■D 


'1      4} 

\   ■        j    ': 


y^ 


Root  of  Molar  staixed  with  Chloride  of  Gold. 

D,  dentine  ;  C.  cement  with  branching  bone-corpuscles :  F^,  dentinal  fibers  with  their  trans- 
verse offshoots  ;  F-,  ramifications  of  dentinal  fibers  and  their  union  with  the  oflFshoots  of  cement- 
corpuscles.    Magnified  1200  diameters. 


offshoots  of  the  protoplasmic  bodies  of  the  cementum,  or  the  light 
net-work  of  the  basis-substance  of  the  dentine  is  in  communi- 
cation with  that  of  the  basis-substance  of  the  cementum." 

The  latter  condition  prevails  at  the  periphery  of  the  neck  of 
the  tooth,  where  the  basis-substance  of  the  dentine  is  pierced 
not  by  larger  offshoots  of  the  dentinal  fibers,  but  only  by  a  deh- 
cate  net-work,  through  which  the  connection  between  dentine 
and  cementum  is  indirectly  established. 

Where  the  dentine  is  in  contact  with  the  pulp,  the  dentinal 


74       THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH. 

fibers  communicate  directly  with  the  odontoblasts  (John  Tomes) 
in  a  growing  tooth,  and  with  the  protoplasmic  bodies  of  the  pulp 
in  a  fully-developed  condition,  where  no  regular  odontoblasts 
can  be  seen. 

In  cross-sections  of  dentine  the  dentinal  canaliculi  are  visible 
in  the  shape  of  circular  or  oblong  holes ;  the  center  of  each  is 
occupied  by  the  dentinal  fiber,  wdiich  has  the  shape  of  a  small 
roundish  dot.  Again  we  see  that  the  periphery  of  the  dentinal 
canaliculus  is  sharply  marked,  and  repeatedly  interrupted  by 
light  offshoots  leading  into  the  light  net-work  that  pierces  the 
basis-substance  between  the  canaliculi.  The  central  fibers  look 
very  distinct  and  dark  violet  in  specimens  stained  with  chloride 
of  gold,  and  send  slender,  conical,  radiated  offshoots  through  the 
surrounding  dentinal  canaliculi,  respectively  toward  the  mouth 
of  the  light  interruptions  in  their  walls. 

Fig.  43. 


^3  1^"  \f^-^~^r—I' 


_S- 


"1 


^^^vLt„-  ^-  uoK/^^'^^^:' 


■£■ 


Ckoss-Sectiox  of  Dextine  of  Incisor.  Cross-Sectio\  of  Dentine  of  Incisor. 

Stained   ■vfith    Chloride    of    Gold.  Stained   with    Chloride    op   Gold. 

Main  Mass  of  Dentine.  View    from    Outer     Periphery    of 

Dentine,  near  Enamel. 

F,  dentinal  canaliculi  with  the  central  dentinal  fibers,  the  latter  with  star-like  offshoots ;  E, 
the  basis-substance  between  the  canaliculi,  pierced  by  a  delicate  light  net-work.  Magnified 
2000  diameters. 

In  directly  transverse  sections,  one,  two,  or  sometimes  even 
three  such  offshoots  can  be  seen  in  a  star-like  arrangement. 
Each  offshoot  springs  with  a  broad  base  from  the  central  den- 
tinal fiber,  while  its  pointed  end  always  is  directed  toward  the 
perforation  in  the  wall  of  the  canaliculus,  where,  as  a  rule,  it  is 
lost  to  sight.  Slightly  oblique  sections  of  the  canaliculi  exhibit 
both  transverse  and  longitudinal  projections  of  the  dentinal 
fibers.  In  such  an  oblique  section  we  may  succeed,  by  cautiously 
changing  the  focus,  in  seeing  star-like  radiated  offshoots  up  to 
five  in  number,  all  arising  from  a  single  dentinal  fiber. 

Toward  the  boundary  between  dentine  and  enamel,  and 
dentine  and  cementum,  as  is  well  known,  the  dentinal  canaliculi 


THE    MINUTE    STRUCTURE    OF    DENTINE,  75 

niraify,  and  according  to  their  ramifications  also  the  dentinal 
fibers  bifurcate,  becoming  the  thinner  the  nearer  thej  are  to  the 
surface  of  the  dentine.  Both  longitudinal  and  transverse  sec- 
tions of  this  part  of  the  dentine  show  details  identical  with  the 
main  mass  of  the  dentine,  the  only  difference  being  that  near 
the  periphery  of  the  dentine  the  fibers  are  more  delicate  and 
more  closely  arranged.     (See  Fig.  43.) 

In  some  teeth  I  have  met  on  the  periphery  of  the  dentine  of 
the  crown  with  the  so-called  "  interglobular  spaces"  (Czermak), 
which  may  be  considered  as  remnants  of  the  embryonic  con- 
dition of  the  dentine.  They  represent  lacunae  of  greatly  vary- 
ing sizes,  bounded  by  curved  lines,  the  convexities  of  which  are 
directed  toward  the  central  cavity.  These  spaces  sometimes 
contain  protoplasm, — that  is  to  say,  embryonal  elements  which 
have  not  been  transformed  into  basis-substance  and  not  calcified. 
The  dentinal  fibers  enter  the  protoplasmic  bodies,  and  each  fiber 
is  united  with  the  net-work  of  the  protoplasm  by  means  of  deli- 
cate thorn-like  projections.  At  other  times  the  1)asis-substance 
of  the  dentine  is  developed  within  the  interglobular  spaces,  but 
devoid  of  lime-salts.  In  this  instance  the  dentinal  fibers,  with- 
out investment  and  without  changing  their  course,  pierce  the 
basis-substance  and  send  ofiTshoots  to  this  through  the  surround- 
ing light  spaces. 

The  dentine  shows,  in  general,  though  not  constantly,  peculiar 
formations  where  it  approaches  the  enamel  and  cementum. 
These  formations,  however,  being  in  close  relation  to  the  cover- 
ing tissues  of  the  tooth,  I  prefer  to  describe  in  the  chapter  on 
cementum  and  enamel. 

Results. — The  dentinal  canaliculi  are  excavations  in  the  basis- 
substance  of  the  dentine,  each  containing  in  its  center  a  fhei^  of 
living  matter.  Besides  the  dentinal  canaliculi,  there  exists  an  ex- 
tremely delicate  net-work  within  the  basis-substance  of  the  den- 
tine, into  which  innumerable  ofi:shoots  of  the  dentinal  fibers  pass. 
Although  evidently,  by  reason  of  its  delicacy,  we  cannot  trace 
the  living  matter  throughout  the  whole  net-work  in  the  basis- 
substance,  we  are  justified  in  assuming  that  not  only  are  the  den- 
tinal canaliculi,  but  so  also  is  the  whole  basis-substance  of  the 
dentine,  pierced  by  a  delicate  net-work  of  living  matter.  The 
living  matter  of  the  dentine  is  in  direct  union  with  that  of  the 
protoplasmic  bodies  of  the  pulp,  of  the  cementum,  and  of  the 
enamel. 


tb  THE    ANATOMY    AND    PATHOLOItY    OF    THE    TEETH. 

Further  researches  into  the  minute  structure  of  dentine  have 
been  made  by  John  I.  Hart,*  of  which  the  following  is  an  abstract  : 

"Method. — A  freshly  extracted  tooth,  preferably  a  deciduous 
one,  is  sawed  into  sections,  either  vertical  or  transverse,  with 
the  precaution  that  the  tooth,  and  the  instrument  employed,  are 
kept  constantly  moist  with  a  one  or  two  per  cent,  solution  of 
sodium  chloride.  The  object  of  this  procedure  is  to  prevent  the 
drying  up  and  consequent  shrinkage  of  all  soft  constituents  of 
the  dentine, — viz,  the  dentinal  fibers  and  their  offshoots.  The 
slab  thus  obtained  is  ground  first  with  a  coarse  corundum-wheel 
on  the  lathe,  and  afterward  on  a  corundum-slab  of  medium 
grit,  always  under  a  weak  solution  of  table-salt.  I  wish  to  lay 
stress  upon  the  fact  that  the  ground  slabs  should  not  be  kept 
longer  than  two  hours  in  the  salt  solution,  lest  the  dentinal 
fibers  should  become  hydropic,  and,  swelling  up,  completely 
fill  the  canalieuli.  Before  staining,  with  a  camel's-hair  brush 
cleanse  the  specimen  of  the  adhering  debris  resulting  from  the 
grinding.  The  next  process  is  staining  with  a  one-half  of  one 
per  cent,  solution  of  chloride  of  gold,  or  a  one  per  cent,  solution 
of  hyperosmic  acid.  Since  the  latter  has  proved  inferior  to 
the  former,  it  has  been  abandoned,  and  chloride  of  gold  is  ex- 
clusively employed.  Two  waj's  have  been  adopted.  Pour  the 
chloride-of-gold  solution  over  the  slab  and  leave  it  immersed  two 
hours,  carefully  shutting  ofi"  the  light;  then  transfer  the  slab 
with  a  wooden  spatula,  carefully  avoiding  all  metallic  instru- 
ments, into  a  six  per  cent,  solution  of  glacial  acetic  acid  for  two 
hours.  Repeat  this  procedure, — viz,  staining  with  the  gold 
salt  and  decalcifying  with  acetic  acid  from  ten  to  twelve  hours, 
after  which  the  now  pliable  slab  is  left  exposed  to  strong  day- 
light in  distilled  water  until  it  has  assumed  a  dark-violet  color; 
or  expose  the  slab  to  the  action  of  the  gold  salts  for  ten  hours, 
and  then  to  the  solution  of  acetic  acid  for  the  same  length  of 
time,  and  expose  to  light  in  distilled  water.  The  latter  method 
is  preferable,  although  the  specimens  are  sometimes  partially 
overstained  and  become  too  dark  for  examination.  After  the 
required  color  is  reached,  brush  the  specimen  gently  in  order  to 
remove  the  precipitations  of  the  gold  salt,  and  mount  in  chemi- 
cally-pure glycerin. 

"  There  is  a  marked  difference  in  the  behavior  of  enamel  and 
that  of  dentine  in  the  process  of  decalcification  by  acetic  acid. 

*  ••  Minute  Structure  of  Dentine.  '     Dental  Cosmos,  1891. 


THE    MINUTE    STRUCTURE    OF    DENTINE.  77 

Enamel  at  first  breaks  up  into  prisms  with  transverse  blocklets, 
similar  to  those  obtained  by  treatment  with  dilute  hydrochloric 
acid.  Upon  the  approach  of  complete  decalcification,  the 
enamel  becomes  extremely  brittle,  and  breaks  up  into  small 
pieces  if  the  least  pressure  is  exerted  upon  it.  After  complete 
removal  of  the  lime-salts,  there  is  left,  as  first  seen  and  described 
by  Dr.  Frank  Abbott  as  early  as  1878,  only  a  delicate  reticulum, 
— the  last  residue  of  organic  material. 

"  Dentine  resembles  enamel  only  in  this  particular,  that  in 
incomplete  decalcification,  blocklets  of  lime-salts  are  seen 
throughout  the  basis-substance.  After  complete  decalcification 
a  tough,  pliable  slab  is  left,  which,  even  though  exposed  to  some 
pressure,  will  not  break  asunder.  Obviously  the  glue-yielding 
basis-substance  and  its  tenants  are  not  corroded  or  affected  in 
the  least  by  the  six  per  cent,  solution  of  acetic  acid.  All  this 
acid  accomplishes  is  the  removal  of  the  lime-salts  deposited  in 
the  basis-substance,  thereby  rendering  clear  its  minutest  struc- 
ture. Exposure  of  a  ground  slab  of  dentine  to  the  action  of 
the  gold  solution  for  three  hours  renders  the  dentinal  fibers 
plainly  visible  and  tinted  a  pale  violet.  Exposure  of  six  hours 
will  stain  the  dentinal  fibers  dark  violet,  and  will  bring  out 
clearly  the  broader  offshoots.  An  exposure  of  from  nine  to  ten 
hours  is  necessary  to  bring  forth  the  more  minute  conical  off- 
shoots emanating  from  the  dentinal  fibers  and  the  minutest 
structure  in  the  basis-substance. 

"  Main  Mass  of  Dentine.— If  successfully  stained  portions  are 
placed  under  an  amplifying  power  of  from  1000  to  1200 
diameters,  striking  features  become  recognizable  in  the  dentinal 
fibers  themselves.  Should  the  method  described  above  be  faith- 
fully carried  out,  we  will  invariably  see  portions  of  a  varying 
extent  suitable  for  the  amplification  just  stated.  It  makes  no 
difference  whether  water  or  cedar-oil  immersion  is  resorted  to. 

"  The  dentinal  fibers  in  the  main  mass  of  the  dentine  do  not 
look  homogeneous,  as  in  the  unstained  condition,  but  appear 
hollowed  out  in  their  interior  by  light  spaces,  so-called 
vacuoles,  of  greatly  varying  sizes.  These  vacuoles  are  plainly 
visible  if  the  ground  slab  is  left  exposed  for  the  shortest  possible 
time  to  the  salt  water.  If  this  exposure  is  protracted  for  days, 
the  vacuoles  will  appear  enlarged  and  almost  continuous  within 
the  dentinal  fibers.  Both  longitudinal  and  transverse  sections 
exhibit  the  vacuoles:  I  have  obtained  the  most  distinct  image, 


78  THE    ANATO.MY    A^'D    PATHOLOGY    OF    THE    TEETH. 

however,  in  thin  lougituclinal  sections,  where  but  one  layer  of 
dentinal  fibers  was  visible.     (See  Fig.  44.) 

"From  the  rather  uneven  periphery  of  the  dentinal  fibers 
arise  a  smaller  number  of  broad  and  a  large  number  of  delicate 
conical  offshoots,  all  of  a  dark-violet  tint.  These  offshoots 
pierce  in  an  almost  rectangular  direction  the  light  space  of  the 
dentinal  canaliculus,  and  inosculate  with  a  minute  dark-blue  net- 
work pervading  the  whole  basis-substance  of  the  dentine.  This 
net-w^ork  being  present  throughout  the  basis-substance,  serves 

Fig.  41. 


Main  Mass  of  Destine  of   a  Temporary  Tooth,  Stained   with   Chloride  of  Gold, 
Decalcified  -with  Acetic  Acid. 

F,  F,  dentinal  fibers,  partly  vacuoled ;   B,  B,  basis-substance,  traversed  by  a  reticulum. 
Magnified  1200  diameters. 

for  a  direct  interconnection  of  all  dentinal  fibers.  The  net-work 
appears  uninterrupted  wherever  sufficiently  stained,  although  w^e 
may  fail  to  trace  the  connections  in  some  limited  portions  ot 
the  basis-substance.  In  transverse  sections  of  the  dentinal 
canaliculi,  such  as  we  invariably  obtain  in  longitudinal  sections 
of  the  crown,  and,  as  a  matter  of  course,  in  transverse  sections 
of  any  part  of  the  tooth,  we  notice  features  identical  with  those 
of  longitudinal  sections.     (See  Fig.  45.) 


THE    MINUTE    STRUCTURE    OF    DENTINE. 


79 


"  The  dentiaal  fibers  of  somewhat  varying  diameters  exhibit 
hollow  centers  in  many  instances.  From  their  periphery,  broad 
and  narrow  offshoots  spring  forth  in  a  considerabh'  larger 
number  than  ever  visible  in  sections  of  teeth  not  treated  with 
chloride  of  gold.  The  basis-substance  appears  to  be  traversed 
by  a  dark-violet  reticulum  of  the  same  character  as  that  of  longi- 
tudinal sections.  Oblique  sections  will  of  necessity  show  an 
apparently  larger  number  of  dentinal  canaliculi  and  their  tenants 
than  longitudinal  or  transverse  sections  in  a  given  area  of  den- 
tine. Here  we  often  obtain  the  impression  that  rectangular  off- 
shoots of  one  dentinal  fiber  inosculate  directly  with  neighboring 
fibers,  thus  furnishing  a  pretty  figure  of  a  ladder  with  minute 
rungs. 

Fig.  45. 


Dentike  of  Temporary   Tooth.    Transverse   Section   of   Canaliculi,  Stained  vrirH 
Chloride  of  Gold,  Decalcified  with  Acetic  Acid. 

F,  F,  dentinal  fibers,  with  radiating  oflFshoots  piercing  the  space  of  the  canaliculi ;  B,  B,  basis- 
substance  traversed  by  a  delicate  reticulum,  in  connection  with  the  dentinal  fiber.  Magnified 
1200  diameters. 

"  x\ll  that  I  have  described  thus  far  as  being  present  in  the 
main  mass  of  the  dentine  is  plainly  visible  only  in  the  dentine  of 
teeth  that  were  alive  at  the  time  of  extraction.  If  life  has  been 
destroyed  to  a  varying  extent  by  an  alveolar  abscess  or  pyorrhea 
alveolaris,  the  image  furnished  by  the  dentine  is  so  characteristic 
that  we  recognize  at  the  first  glance  the  extinction  of  life. 
Several  times  have  I  ground  teeth  without  knowing  that  they 
were  dead.     The  microscope  revealed  the  fact.     (See  Fig.  46.) 

"  In  longitudinal  sections,  only  the  canaliculi  are  conspicuously 
prominent,  exhibiting  delicate  and  numerous  interruptions 
along  their  walls.     The  dentinal  fibers  appear  shriveled  up  to 


80 


THE    ANATOMY    AND    PATHOLO(:^Y    OF    THE    TEETH. 


rows  of  minute  granules,  not  always  in  the  center  of  the  canali- 
culus, but  frequently  quite  near  to  one  of  the  walls.  The  gran- 
ules often  appear  interrupted  to  a  considerable  extent,  and  some- 
times the  remnants  of  the  dentinal  fibers  are  missing  altogether. 
IS^o  conical  offshoots  emanate  from  the  remnants  of  the  dentinal 
fibers.  The  basis-substance  shows  a  rather  faint  and  indistinct 
reticulum,  lacking  connections  in  numerous  places.  In  trans- 
verse sections  of  dead  portions  of  the  dentine  we  obtain  a  strik- 
ing image.     (See  Fig.  47.) 

Fig.  46. 


Destine  of  a  Dead  Temporary  Tooth.  Stained  -n-iTH  Chloride   of  Gold,  Decalci- 
fied WITH  Acetic  Acid. 

(J,  C,  canalieuli,  holding  shriveled  dentinal  fibers  ;  B,  B,  basis-substanee,  holding  a  shriveled 
reticulum.    Magnified  1200  diameters. 


"  AVe  see  the  dentine  pierced  by  light  spaces  at  almost  uniform 
distances,  many  of  which  contain  dark-violet  granules  or  ves- 
tiges of  a  previous  dentinal  fiber.  There  are  but  scanty  and 
incomplete  indications  of  conical  offshoots  emanating  from  the 
shrunken  dentinal  fibers.  The  basis-substance  is  of  the  same 
character  as  found  in  longitudinal  sections.  The  basis-substance 
shows  a  rather  indistinct  dark-violet  reticulum  with  numerous 
interruptions.      The  facts  here  described  suffice,  in  my  judg- 


THE    MINUTE    STKUCTURE    OF    DEXTIXE.  81 

ment,  to  determine  the  nature  of  the  reticulum  pervading  the 
whole  of  the  dentine ;  it  is  of  necessity  the  living  matter  which 
is  plainly  marked  in  living,  and  shriveled  and  reduced  to  a  row 
of  granules  in  dead  teeth.  Since  we  know  of  no  tissue  consti- 
tuted  of  nerves,  we  cannot  support  the  suggestion  of  John 
Tomes,  that  dentinal  fibers  are  but  nerve-fibers  carrying  sensa- 
tion from  the  periphery  to  the  center.  Since  we  know  that  non- 
medullated  nerve-fibers  have  the  same  structure  as  the  dentinal 
fibers,  we  must  conclude  that  both  the  nerves  and  dentinal  fibers 
are  made  up  of  living  or  contractile  matter,  the  contraction  of 
which  is  facilitated  by  the  presence  of  vacuoles.  For,  according 
to  modern  researches,  the  conduction  of  sensation  centripetally 


Fig.  41 


Dentine  OF  a  Dead  Temporary  Tooth.     Teaxsveese  Section  of  Caxaliculi,  Stained 
•WITH  Chloride  of  Gold,  Decalcified  iriTH  Acetic  Acid. 

C,  C,  dentinal  canaliculi,  holding  shriveled  dentinal  fibers  ;  B,  B,  basis-substance,  containing 
a  shriveled,  indistinct  reticulum.    Magnified  1200  diameters. 

and  of  motion  centrifugally  is  ver}''  probably  instituted  by  the 
contraction  of  living  matter. 

"  Interzonal  Layer  between  Dentine  and  Enamel. — In  all  the 
provisional  teeth  that  I  have  examined,  a  zone  of  varying  breadth 
was  visible  along  the  outer  periphery  of  the  dentine,  conspicuous 
by  a  darker  violet  stain  than  the  rest  of  the  dentine.  In  fact, 
this  region  is  rather  prone  to  be  overstained  and  become  too 
dark  for  examination  with  high  powers ;  hence,  we  should  ex- 
amine this  region  before  it  has  assumed  a  deep  stain,  owing  to  a 
protracted  exposure  to  light.  The  first  feature  which  strikes  us 
upon  approaching  the  outer  periphery  of  the  dentine  is  the 

7 


82 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


beaded  appearance  of  the  dentinal  fibers,  lacking  vacuoles  in  this 
situation.  The  fibers  are  bifurcating,  as  is  Avell  known,  and, 
becoming  more  and  more  delicate,  correspondingly  exhibit  more 
and  more  beads.  The  reticulum  into  which  the  lateral  conicnl 
ofl:shoots  of  the  dentinal  fibers  inosculate  is  extremely  dense, — 
much  more  so  than  in  the  rest  of  the  dentine.  The  densely 
reticulated  zone  usually  corresponds  to  the  depth  of  the  bifur- 
cations of  the  dentinal  fibers;  in  other  words,  it  commences  in 
a  rather  abrupt  line  in  the  height  in  which  bifurcations  begin 
to  appear.     (See  Fig.  48.) 

Fig.  48. 


Dentine  of  Temporary  Tooth,  near  Enamel,  Stained  ■^vith  Chloride  of  Gold.  De- 
calcikied  avith  Acetic  Acid. 

B.B,  boundary  of  dentine  toward  enamel;  /, /,  interzonal  layer  (Atkinson \  with  a  dense 
reticulum,  dentinal  fibers  bifurcating ;  D,  D,  main  mass  of  dentine,  holding  beaded  dentinal 
fibers.    Magnified  1200  diameters. 


"  The  presence  of  this  dense  reticulum  of  living  matter  evidentlj^ 
explains  the  fact  that  the  interzonal  layer  between  enamel  and 
dentine  is  so  extremely  sensitive.  I  am  sure  that  every  dentist 
is  made  aware  of  this  striking  fact  when  cutting  into  dentine. 
The  dentinal  fibers  rarely  enter  the  enamel  in  human  teeth,  but 
the  reticulum  of  the  dentine  is  continuous  with  that  of  the 
enamel.      This   connection,   however,  I   w^as    unable   to  trace 


THE    MINUTE    STRUCTURE    OF    DENTINE.  83 

myself,  as  in  all  mj  specimens  the  enamel  was  dissolved  and 
removed  by  the  camel's-hair  brush  prior  to  mounting. 

"Interzonal  Layer  between  Dentine  and  Cementum  at  the 
Neck  of  the  Tooth. — Ever  since  John  Tomes  drew  attention  to 
the  peculiar  fact  that  the  dentinal  fibers  stopped  short  of  the 
cementum,  special  attention  has  been  paid  to  this  region  of  the 
dentine,  since  it  is  also  known  to  be  more  sensitive  than  the  rest 
of  the  dentine.  According  to  Tomes,  '  the  greater  degree  of 
sensitiveness  observable  in  the  dentine  immediately  below  the- 
enamel, — that  is,  at  the  point  of  ultimate  distribution  of  the  den- 
tinal "  tubes,"  and  consequently  of  their  contents, — may  be  fully 
accounted  for  on  the  supposition  that  the  latter  are  organs  of 
sensation,  the  highest  sensibility  of  which  is  confined  to  their 
branches.' 

"  This  hypothesis  does  not  find  foundation  in  the  region  of  the 
neck,  where  bifurcations  of  dentinal  fibers  are  often  missing  or 
are  scanty.  There  is  only  a  uniformly  granular  layer  visible  in 
unstained  and  ground  specimens  between  the  surface  of  the 
dentine  and  the  terminal  points  of  the  dentinal  fibers.  Still,  the 
sensitiveness  at  the  neck  is  undoubtedly  even  greater  than  that 
of  the  interzonal  layer  of  the  crown.  Bodecker  drew  attention 
to  the  fact  that  in  the  great  majority  of  teeth  the  finest  ter- 
minations of  the  dentinal  fibers  are  lost  to  sight  in  a  net-work 
somewhat  coarser  than  that  of  the  basis-substance  of  ordinary 
dentine.  Sometimes,  he  says,  the  dentinal  canaliculi  upon  ap- 
proaching the  periphery  become  slightly  dilated,  so  as  to  pro- 
duce slender  pear-shaped  cavities,  in  accordance  with  which  the 
terminating  dentinal  fibers  exhibit  slight  enlargements. 

"  I  can  corroborate  this  statement  from  what  I  have  seen  in 
my  own  specimens  of  temporary  teeth.  Several  times  I  have 
met  with  peculiar  formations  in  this  region,  which,  as  far  as  I 
am  aware,  have  not  as  yet  been  described.  (See  Fig.  49.)  In 
unstained  slabs  of  temporary  teeth  I  have  seen  coarsely  granular 
layers  in  the  dentine  at  the  region  of  the  neck,  with  which  the 
dentinal  fibers  directly  inosculated.  After  deep  staining  with 
chloride  of  gold,  the  granular  layers  became  dark  violet  and 
easily  recognizable  with  low  powers  of  the  microscope.  I  found, 
as  a  rule,  one  or  two  granular  layers  like  narrow  ribbons  run- 
ning along  the  outer  periphery  of  the  dentine,  close  to  the 
cementum.  A  much  more  irregular  and  broader  granular 
layer  was  seen  at  a  certain  distance  below  the  surface,  produc- 


84 


THE    ANATOMY    AND    PATH0L0C4Y    OF    THE    TEETH. 


ing  wavy  lines,  and  being  in  connection  externally  witli  a  more 
uniformly  granulated  layer,  and  internall}^  with  the  dentinal 
fibers.  This  peculiar  configuration  was  plainest  at  the  portion 
of  the  cementum  made  up  of  spindles  at  the  neck  of  the  tooth, 
and  gradually  faded  downward,  where  the  lamellated  layer  of  the 
cementum  began  to  make  its  appearance.  High  powers  of  the 
microscope  revealed  the  intimate  structure  of  this  portion. 
(See  Fig.  50.) 

Fig.  49. 


Neck  of  Texiporary  Tooth.    Loxgitudinal  Ssctiox,  Stained  with  Chloride  of  Gold, 
Decalcified  with  Acetic  Acid. 

D,  D,  dentine,  main  mass ;  N,  N,  dentine  of  neck,  bordered  upward  and  downward  by  coarsely 
granular  layers;  C,  C,  cementum  of  neck;  P,  P,  shreds  of  pericementum.  Magnified  400 
diameters. 

"  The  fi.bers  in  this  situation  appear  reduced  in  caliber,  and 
show  a  beaded  structure  much  the  same  as  at  the  periphery  of 
the  crown.  These  fibers  either  terminate  in  pear-shaped  en- 
largements, or  in  irregularly-shaped  dark-violet  lumps,  which 
send  delicate  ofi:'shoots  in  all  directions,  serving  as  an  intercom- 
munication between  them.  The  large  number  of  these  lumps 
causes  the  granular  appearance  of  the  dentine.  The  following 
broader  zone,  which  with  lower  powers  has  appeared  uniformly 
granular,  is  now  dissolved  into  a  rather  coarse  reticulum — much 
coarser  than  that  of  the  interzonal  layer  of  the  crown.  This 
reticulum  shows  stray  irregular  fibers.  Both  the  latter  and  the 
lumps  are  in  close  connection  with  the  reticulum. 


THE    MINUTE    STRUCTURE    OF    DENTINE. 


85 


"At  the  outermost  periphery  we  again  notice  one  or  two  rows 
of  enlargements,  which,  judging  from  the  regularity  of  their 
arrangement,  correspond  to  the  bases  of  the  spindles,  building 
up  the  cementum  of  the  neck.  This  large  amount  of  living 
matter  satisfactorily  explains  the  extreme  sensitiveness  of  the 
region  of  the  neck. 

"Results. — To  sum  up  my  observations,  I  must  maintain  the 
presence  of  a  reticulum  of  living  matter  throughout  the  dentine. 

Fig.  50. 


Dentine  of  Neck  op  Temporary  Tooth,  Stained  with  Chloride  of  Gold,  Decalci- 
fied WITH  Acetic  Acid. 

D,  D,  dentine;  G,  G,  coarse  globules,  into  which  the  dentinal  fibers  inosculate;  N,  jV,  den- 
tine of  neck,  with  a  coarse  reticulum,  lacking  fibers;  C,  C,  cementum  of  neck,  bordered  by  a 
granular  layer  toward  the  dentine.     Magnified  1200  diameters. 

It  is  decidedly  coarser  than  that  seen  and  described  by  Frank 
Abbott  in  the  enamel.  It  is  most  delicate  in  the  interzonal 
layer  of  the  crown  between  dentine  and  enamel,  and  coarsest  in 
the  region  of  the  neck  bordering  on  the  cementum. 

"  My  assertion  finds  proof  by  comparison  of  living  with  dead 
teeth,  for  in  the  latter  the  dentinal  fibers  were  reduced  to  a 
series  of  granules,  and  the  basis-substance  appears  irregularly 
dotted  or  spotted,  instead  of  being  reticular.     The  microscope 


86       THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH. 

therefore  easily  reveals  the  difference  between  living  and  dead 
teeth.  Another  point  of  confirmation  is  that  the  portions  of  the 
dentine  being  most  sensitive  are  richest  in  the  supply  of  living 
matter,  not  in  that  of  the  fibers  which  are  missing  in  the  inter- 
zonal layer  of  the  dentine  of  the  neck,  but  in  that  of  the  basis- 
substance." 

Further  researches  into  the  presence  of  the  reticulum  in 
dentine  have  been  published  by  Carl  Heitzmann,*  as  follows  : 

"  Dr.  Bodecker  had  collected  a  large  number  of  teeth  that  were 
filled  for  months  and  years.  The  first  tooth  he  ground  thin  was 
a  bicuspid  with  two  cavities  in  its  crown;  one  filled  with  cement, 
the  other  with  silver  amalgam, — both  plugs  having  been  in  the 
cavities  for  years.  How  great  was  his  surprise  when,  examin- 
ing the  border  of  the  cavity  previously  filled  with  amalgam,  he 
saw  a  dark-brown  discoloration  of  the  dentine,  not  directly  along 
the  border  of  the  cavity,  but  some  distance  away  from  it,  and 
in  this  brown  zone  the  dentinal  canaliculi,  respectively  their 
tenants,  the  dentinal  fibers,  crowded  with  black  dots,  and  their 
offshoots  rendered  wonderfully  plain  by  a  black  deposit.  In  the 
darkest  portion  the  reticulum  was  easily  seen  with  compara- 
tively low  powers  of  the  microscope, — viz,  500  diameters.  (See 
Fig.  51.) 

"  The  border  of  the  cavity  is,  in  the  upper  portion,  seen  in 
the  breadth  of  the  specimen,  and  here  it  holds  a  number  of 
black  metallic  particles,  evidently  not  of  the  amalgam  itself, 
but  of  a  sulphur-combination  of  the  silver  or  quicksilver.  The 
zone  of  the  dentine  directly  bordering  the  cavity  is,  apparently, 
destitute  of  structure,  showing  but  faint  traces  of  canaliculi ; 
of  a  high  refraction,  obviously  in  a  state  of  consolidation,  a 
reactive  process  subsequent  to  the  filling.  Close  beneath  this 
consolidated  layer  follows  a  dark-brown  zone,  diffusively  pig- 
mented, and  here  we  see  the  dentinal  canaliculi  crowded  with 
black  metallic  particles,  considerably  widened  and  sending  black 
ofi^shoots  into  the  basis-substance  between  the  canaliculi.  The 
ofl'shoots  are  comparatively  scarce  and  large  toward  the  enamel, 
where  the  unstained  canaliculi  show  only  the  usual  bifurcation. 
The  offshoots  are  more  numerous  upon  entering  the  dark-brown 
region  of  the  dentine,  and  in  the  darkest  portion  are  so  numer- 

*  "  Demonstration  of  the  Reticulum  in  Dentine  with  Low  Powers  of  the  Micro- 
scope."    Transactions  of  the  New  York  Odontological  Society,  1892. 


THE    MIXIITE    STRUCTURE    OF    DENTINE. 


87 


ous  and  so  delicate  tliat  the  power  of  five  liiindred  diameters  is 
iiisufiicient  to  dissolve  the  minutest  branches,  all  of  which  in- 
osculate into  an  extremely  delicate  hlack  reticulum.  All  the 
features,  the  coarse  and  tine  offshoots  and  their  union  into  a  re- 


Fio.  51. 


Ground  Bicuspid.    Cavity  of  the  Crown  previously  filled  with  AMALGAXf. 

E.  enamel;  D,  D,  dentine  ;  B,  border  of  cavity  ;  .S",  solidified  dentine  along  the  border  of  the 
cavity ;  R,  reticulum,  brought  forth  by  the  amalgam.    Magnified  500  diameters. 

ticulum,  are  identical  with  the  image  obtained  by  John  I.  Hart 
in  living  dentine,  treated  with  chloride  of  gold. 

"How  did  the  metallic  particles  reach  the  dentinal  canaliculi, 


88  ,     THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

and  produce  such  an  image  at  a  certain  distance  away  from  the 
border  of  the  cavity  ?  There  is  but  one  answer  possible  to  this 
query.  The  metallic  particles  were  taken  into  the  living  matter, 
probably  before  the  consolidation  was  accomplished  at  the  bor- 
der of  the  cavity,  and  carried  farther,  at  the  same  time  render- 
ing visible  the  reticulum,  interconnecting  the  dentinal  fibers. 
It  would  be  impossible  to  understand  the  loading  of  the  den- 
tinal fibers,  which  run  a  parallel  course  and  are  separated  from 
one  another  by  the  intervening  basis-substance,  unless  by  the 
presence  of  transverse  connections  of  the  fibers,  as  actually 
shown  by  the  reticulum.  This  reticulum  is,  in  fact,  so  plain 
that  any  tyro  must  see  it,  and  the  specimen  alone  is  suflicient  to 
remove  the  doubts  of  even  the  most  skeptical  minds. 

"  Fig.  52  represents  the  neck  of  a  molar  whose  pulp  years 
ago  was  treated  by  AYilhelm  Herbst,  of  Bremen,  Germany,  with 
his  method,  made  known  in  this  country  by  Dr.  Bodecker.  Dr. 
Herbst  applies  cobalt  upon  the  exposed  or  inflamed  pulp  of  the 
crown ;  a  few  days  afterward  he  excises  the  pulp  down  to  the 
root-canals;  introduces  tin  foil,  which  he  grinds  down  at  the 
bottom  of  the  cavity,  thus  shutting  off  the  pulp  of  the  root- 
canals  from  contact  with  air,  or  other  filling-materials  placed 
into  the  cavity  of  the  crown.  The  remarkable  outcome  of 
Bodecker's  examination  of  the  teeth  sent  by  Herbst  is  that  the 
pulp  remains  alive  in  the  root-canal,  and  is  sufiicient  to  endow 
with  life  the  whole  tooth,  though  its  crown  is  entirely  deprived 
of  its  pulp.  This  fact  becomes  intelligible  only  upon  the  pres- 
ence of  interconnections  between  the  parallel  dentinal  fibrillfe ; 
for  the  dentinal  fibers  could  not  possibly  be  kept  alive  in  the 
crown,  unless  by  unions  with  the  fibrillse  of  the  roots,  the  only 
ones  kept  directly  alive  by  the  pulp-tissue  of  the  roots.  This  is 
an  indirect,  though  stringent  proof  of  the  presence  of  the  reticu- 
lum. The  direct  proof  is  furnished  by  the  visible  interconnec- 
tions of  the  fibrillse  along  the  neck  of  the  tooth,  of  a  brownish 
color,  in  a  slightly  brownish  basis-substance.  After  having 
examined  many  hundreds  of  teeth  under  the  microscope  in  all 
sorts  of  pathological  changes,  I  have  never  met  with  such  a  dis- 
coloration in  the  dentine  so  frequently  observed  in  the  enamel. 
It  is  quite  possible  and  reasonable  to  assume  that  the  metallic 
salt,  originated  at  the  border  of  the  cavity,  was  transferred  into 
the  dentinal  fibers  and  their  offshoots,  and  was,  at  last,  depos- 
ited in  the  fibrillte  and  their  offshoots  in  the  region  of  the  neck, 


THE    MINUTE    STRUCTURE    OF    DENTINE, 


89 


wliicli,  as  John  I.  Hart's  researches  prove,  abounds'^in  living 
matter  far  in  excess  of  any  other  portion  of  the  dentine.  This, 
I  admit,  is  a  hypothesis,  to  which  I  resort  for  lack  of  a  better 


Ground  Molar.    Thk  Pulp  previocslt  treated  by  the  Heebst  Method.    The  Cav- 
ity FILLED  TTITH  AMALGAM. 

C,  pericementum  ;  0,  osteoid  layer  of  eementum ;  P,  protoplasmic  bodies  at  the  interzonal 
layer  between  eementum  and  dentine  ;  G,  granular  layer  of  dentine  of  tbe  neck ;  JD,  dentine  of 
neck.  A  few  club-shaped  enlargements  of  dentinal  canaliculi.  The  reticulum  brought  forth 
by  the  amalgam.    Magnified  500  diameters. 

explanation ;  it  is  nearest  to  my  mind,  after  thirty-two  years  of 
study  of  the  teeth,  having  become  so  thoroughly  convinced  of 


90  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

the  life  of  all  constituent  tissues  of  the  teeth.  The  specimen 
under  consideration  exhilnts  an  ill-calcified  dentine,  for  it  shows 
numerous  protoplasmic  bodies  at  the  border  of  the  dentine 
toward  the  osteoid  layer  of  the  cementum,  and  club-shaped 
enlargements  of  some  dentinal  fibrillse.  The  granular  layer  of 
Tomes  in  the  dentine  of  the  neck  destitute  of  dentinal  canali- 
culi  is  narrower  than  in  thoroughly  calcified  teeth;  but  present, 
nevertheless." 


CHAPTER    XI. 

THE  MINUTE  STRUCTURE  OP  ENAMEL.* 

The  best  specimens  for  examination  of  enamel  I  obtained  by 
grinding  fresh  teeth,  and  staining  them  for  one  hour  with  a  half 
per  cent,  solution  of  chloride  of  gold. 

Up  to  this  time  the  impression  of  most  examiners  has  been 
that  the  enamel  is  built  up  of  bundles  of  rods,  or  prisms,  cross- 
ing one  another,  and  traversed  by  faint  vertical  lines,  which  give 
each  of  them  the  appearance  of  a  column,  subdivided  into  small 
squares.  The  enamel-rods  doubtless  exist,  and  are  wavy  near 
the  dentine,  and  straight  on  the  periphery  and  the  main  mass  of 
the  enamel.  They  may  be  considered  as  columns  of  a  calcified 
substance,  between  which  minute  spaces  are  left,  analogous  to 
the  cement-substance  of  epithelial  formations. 

In  longitudinal  sections  we  see  delicate  beaded  fibers,  which 
occupy  the  central  portion  of  the  interstices  between  the  enamel- 
rods.  These  fibers  I  propose  hereafter  to  term  the  "  enamel- 
fibers."    (See  Fig.  53.) 

From  such  a  fiber  arise  very  minute  conical  fibrillse,  which 
traverse  the  tiny  intervals  between  the  fiber  and  the  neighboring 
outlines  of  the  rods,  and  fade  away  where  they  enter  the  latter. 
The  columns  of  the  basis-substance  themselves  are  pierced  by 
delicate  canaliculi,  running  in  an  almost  vertical  direction  to  the 
enamel-rods,  regularly  enough  to  give  the  appearance  of  squares, 
although  these  are  much  smaller  than  usually  represented  iji  the 
books.  In  the  midst  of  a  minute  square,  light  canals  are  seen, 
not   infrequently   running   parallel  witli   the    outlines   of   the 

*  "  The  Distribution  of  Living  Matter  in  Human  Dentine,  Cement,  and 
EnameL"    Denial  Cosmos,  1878-1879. 


THE    MINUTE    STRUCTURE    OF    ENAMEL.  91 

enarael-rocl.  The  square  lields  thus  produced  by  the  rectangular 
crossing  of  light  channels  look,  under  the  power  of  1200  diame- 
ters, finely  granular.  In  specimens  not  fully  decalcified  it  is 
impossible  to  decide  whether  there  is  a  light  net-work  within 
the  enamel-prisms  analogous  to  that  in  the  basis-substance  of 
the  dentine  and  cementura,  or  whether  the  granular  appearance 
is  merely  due  to  the  deposition  of  lime-salts.  In  thoroughly  de- 
calcified specimens  of  enamel,  however,  such  as  were  first  made 
by  Dr.  Frank  Abbott,  there  is  no  difficulty  in  seeing,  with  high 
powers,  the  reticular  structure  of  protoplasm. 

Cross-sections  of  the  enamel,  which  we  obtain  also  in  longi- 
tudinal sections  of  the  tooth,  on  account  of  the  different  direc- 
tions of  the  bundles  of  the  enamel-rods,  plainly  exhibit  the 
irregular  polyhedral  fields  of  the  intersected  enamel-rods.     The 

FiC4.  53. 


LOXGITUDIXAL  SeCTIOX  OF  ExAMBL. 

ER,  enamel-rods,  traversed  by  prevailing  vertical  spaces;  EF,  enamel-fibers,  branching  and 
partly  uniting  by  delicate  offshoots.    Magnified  1200  diameters. 

light  interstices  between  the  polyhedral  fields  contain  in  many 
instances  delicate  beaded  fibers,  surrounding  the  polyhedral 
fields  of  the  enamel-rods.  The  fibers,  if  cut  transversely,  have 
tlie  appearance  of  dots.  They  connect  with  one  another  directly 
or  by  means  of  intervening  delicate  threads. 

Extremely  fine  thorns  traverse  in  a  vertical  direction  the  light 
space  between  two  neighboring  enamel-rods,  even  where  a  fiber 
is  not  visible  (see  Eig.  54). 

The  rods  of  the  enamel  are,  on  an  average,  half  the  diameter 
of  the  columns  of  the  basis-substance  in  dentine ;  therefore  four 
columns  of  the  former  will  correspond  to  two  of  the'  latter,  and 
consequently  two  dentinal  fibers  will  answer  to  four  enamel- 
fibers.  Sometimes  in  the  cross-section  of  an  enamel-rod  I  have 
met  with  roundish  formations  occupying  the  center  of  the  rod, 
one  or  two  in  number,  which,  owing  to  a  denser  granulation 
and  a  surrounding  shell,  had  the  appearance  of  nuclei.     The 


92  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

enamel-fibers  run  a  very  straight  course  toward  the  surface, 
and  are,  on  the  average,  a  trifle  thicl^er  here  than  near  the 
boundary  of  the  dentine. 

The  outermost  surface  of  the  enamel  is  covered  by  flat  epi- 
thelia  (Nasmyth's  membrane),  which  in  the  transverse  section 
have  the  appearance  of  shallow  spindles ;  not  infrequently  there 
occurs  also  a  stratified  epithelium  on  the  surface  of  the  tooth. 
The  enamel-fibers  are  in  connection  with  these  epithelial  bodies, 
which,  if  detached,  show  delicate  ofishoots  adhering  in  regular 
intervals — the  broken  enamel-fibers.  Sometimes  the  surface  of 
the  enamel  is  coated  by  a  thin  uniform  layer  of  protoplasm, 
with  regularly  scattered  nuclei.  In  such  an  instance  single  epi- 
thelia  are  not  traceable,  though  scarcely  any  doubt  can  arise 
about  the  epithelial  nature  of  this  layer. 

Fig.  54. 


SI" 


Ceoss-Sectiox  of  Enamel. 

EIi,rods  of  enamel,  partly  exhibiting  formations  like  nuclei ;  the  light  interstices  between 
the  rods  traversed  by  delicate  beaded  fibers,  EF,  or  by  vertical  thorns.  Magnified  2000  diameters. 

•  At  the  place  of  junction  of  the  enamel  with  the  dentine  a 
direct  connection  is  not  infrequently  seen  between  the  enamel- 
and  dentine-fibers.  The  latter,  through  repeated  bifurcations, 
being  closely  brought  together,  continue  their  course  into  the 
enamel-fibers  without  any  interruption.  The  direction  of  the 
fibers  of  the  two  tissues,  however,  is  almost  never  identical,  in- 
asmuch as  the  enamel-rods,  and  consequently  the  enamel-fibers, 
as  a  rule,  owing  to  their  wavy  course  in  this  situation,  are  ob- 
liquely intercepted  upon  the  dentine. 

"We  can  often  trace  dentinal  fibers  up  into  the  enamel  for  a 
varying  distance,  without  finding  a  distinct  union  between  the 
enamel-  and  dentine-fibers,  as  the  former  do  not  reach  the  sur- 
face of  the  dentine,  but  terminate  above  its  level  in  dififerent 
heights,  while  the  zone  close  above  this  is  occupied  by  a  delicate, 


THE    MINUTE    STRUCTURE    OF    EXAMEL.  93 

irregular  net-work,  analogous  to  that  of  the  dentine.  Here  no 
rods  of  enamel  are  visible  either  in  longitudinal  or  transverse 
sections,  but  with  low  powers  of  the  microscope  only  a  finely- 
granular  layer  is  presented. 

In  many  places  the  dentinal  canaliculi,  upon  entering  the 
enamel,  suddenly  become  enlarged,  and  form  more  or  less  dis- 
tinctly spindle-shaped  cavities  of  greatly  varying  diameters,  an- 
alogous to  the  spindle-shaped  enlargements  on  the  boundary  of 
the  cementum.    (See  Fig.  55.)    These  enlargements  either  run 

Fig.  55. 

2L. 


■-BB 


H  F 


Union  of  Dentine  with  Enamel. 

B,  dentine ;  E,  enamel ;  BF,  dentinal  fibers,  in  union  with  large  protoplasmic  bodies,  P,  or 
directly  running  into  enamel-fibers,  EF ;  the  latter  often  are  lost  in  the  delicate,  irregular  net- 
work on  the  bottom  of  the  enamel.    Magnified  1200  diameters. 

in  the  main  direction  of  the  dentinal  canaliculi  or  deviate  ob- 
liquely. They  invariably  contain  protoplasmic  bodies  which 
plainly  show  the  reticular  structure,  and  sometimes  contain  one 
or  more  compact  clusters  to  be  considered  as  nuclei.  The 
spindle-shaped  protoplasmic  bodies  are  in  direct  connection  at 
their  proximate  ends  with  the  terminations  of  the  dentinal  fibers 
that  have  arisen  from  their  repeated  bifurcations,  while  on  the 
distal  end  they  may  show  delicate  fibers,  viz,  enamel-fibers,  or 
delicate  conical  thorns,  traversing  the  light  space  between  the 
surface  of  the  protoplasmic  body  and  the  wall  of  the  cavity. 
These  thorns  are  lost  to  sight  on  passing  into  the  net-work  at 


94  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

the  bottom  of  the  enamel.  In  some  places,  especially  on  the 
cusps,  the  spindle-shaped  enlargements  of  the  dentine-fibers 
are  quite  numerous,  and  of  an  almost  uniform  size  and  direc- 
tion, forming  regular  rows  of  spindles  within  the  enamel.  In 
the  teeth  of  younger  individuals,  the  spindle-shaped  enlarge- 
ments are  comparatively  larger  and  more  regular  than  in  the 
teeth  of  old  people. 

The  boundary-line  between  the  dentine  and  enamel  is  either 
straight  or  slightly  w^avy,  and  with  more  or  less  deep  ba^-like 
excavations,  analogous  to  those  on  the  boundary  between  dentine 
and  cementum.    The  concavities  of  the  bays  are  directed  toward 


DI 


i),  dentine;  E,  enamel;  P,  protoplasmic  formations  at  the  boundary  between  both  tissues  ;: 
EF,  union  -with  enamel-fibers ;  BF,  with  dentine-fibers.    Magnified  1200  diameters. 

the  dentine.  (See  Fig.  56.)  In  this  interzonal  layer  at  the  bottom 
of  the  bays  we  meet  with  fibers  occupying  the  curved  spaces 
between  dentine  and  enamel,  or  we  see  in  a  correspondingly 
bent  course  protoplasmic  bodies  directly  connected  with  the 
dentinal  fibers  downward,  and  with  the  enamel-fibers  upward. 
In  specimens  stained  with  chloride  of  gold,  the  dentine  is  always 
much  deeper  in  color  than  the  enamel,  hence  the  relations  de- 
scribed are  plainly  marked  on  such  specimens. 

Results. — The  enamel  is  traversed  by  fibers  of  living  matter 
located  in  the  interstices  between  the  enamel-rods.  The  fibers 
are  connected  with  one  another  by  delicate  fibrillfe,  piercing  the 
enamel-rods  in  a  vertical  direction.     Besides  these  rectangular 


THE    MINUTE    STRUCTURE    OF    EXAMEL.  95 

unions,  the  basis-substance  is  traversed  bj  a  minute  net-work  of 
living  matter.  The  enamel-fibers  send  conical  thorns  toward 
the  enamel-rods,  and  such  thorns  are  visible  in  all  interstices 
between  the  enamel-rods.  The  enamel-fibers  are  continuous  on 
the  outer  surface  with  the  covering  ]ayer  of  flat  epithelia,  and 
on  the  inner  surface  with  the  dentinal  fibers.  The  latter  con- 
nection is  either  direct  or  indirect  through  a  net-work  of  living 
matter,  or  through  intervening  protoplasmic  bodies  in  the  inter- 
zonal layer. 

Further  researches  in  this  field  have  been  made  by  Frank 
Abbott.*     Of  their  results  the  following  is  an  abstract : 

"  As  to  enamel,  I  have  never  seen  the  minute  relations  marked 
so  plainly  in  permanent  as  I  find  them  in  temporary  teeth. 
Here  the  enamel-rods  are  narrower,  and  the  interstices  between 
them  wider,  than  in  permanent  or  adult  teeth.  A  power  of  500 
diameters  of  the  microscope  is  sufiicient  to  show  plainly  in  the 
temporary  teeth  relations  rendered  visible  in  permanent  teeth, 
only  by  very  much  higher  powers. 

"  The  cut,  Fig.  57,  is  made  from  a  drawing  taken  with  a 
power  of  1200  diameters  (immersion).  In  the  enamel  the 
enamel-rods,  the  fibers  in  the  interstices  between  the  rods,  the 
lateral  offshoots  of  the  fibers,  and  the  light  reticulum  within 
the  rods  are  represented.  As  a  striking  feature,  I  wish  to  em- 
phasize the  direct  connection  of  the  fibers  of  the  dentine  with 
those  of  the  enamel.  Thus  the  width  of  an  enamel-rod  is  in 
full  correspondence  with  the  width  of  the  fields  of  basis- 
substance  of  the  dentine,  after  the  bifurcation  of  the  dentinal 
fibers,  near  the  boundary  between  dentine  and  enamel.  In 
preparing  this  specimen,  it  happened  that  on  several  portions  of 
the  crown  a  larger  portion  of  the  enamel  was  ground  away  than 
was  intended;  so  much  so  that  only  shreds  of  enamel  in  con- 
nection with  the  dentine  were  left.  On  one  of  these  places 
delicate  beaded  fibers  (F)  were  seen,  isolated  at  their  upper 
ends,  while  their  lower  ends  could  be  traced  into  interstices 
between  the  enamel-rods,  and  into  connection  with  the  ends  of 
the  dentinal  fibers.  Xo  doubt  here  the  mechanical  injury  done 
to  the  enamel  has  luckily  led  to  a  tearing  out  of  a  few  enamel- 
fibers,  which  accident  plainly  illustrates  their  presence.'"' 

*  "  The  Minute  Anatomy  of  Dentine  and  Enamel.'-     Dental  Cosmos,  1880. 


96  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

The  same  author,  in  an  article,  "  A  Contribution  to  the  Study 
of  the  Minute  Anatomy  of  Enamel,"*  says, — 

"Dr.  George  W.  "Weld,  in  a  paper  entitled  '  The  Destructive 
Energy  of  the  Tincture  of  the  Chloride  of  Iron  on  the  Teeth : 
an  Experimental  Study,'  read  before  the  iS^ew  York  Odontologi- 
cal  Society,  June  8,  1886,  and  published  in  the  Dental  Cosmos 
for  October,  1886,  page  627,  draws  attention  to  a  novel  method 
of  treating  enamel  for  the  purpose  of  decalcification. 

Fig.  57. 


\ 


V 


^ 


X 


D,  D,  dentine,  with  bifurcating  fibrillar  toward  the  enamel ;  E,  E,  enamel  with  beaded  fibrillaj 
between  the  rods ;  /",  free  fibrillse  of  enamel,  the  rods  being  torn  away.    Magnified  1203  diameters. 

"  Dr.  Weld  minutely  describes  how  a  specimen  (thin  slab)  of 
enamel  previously  treated  with  a  six  per  cent,  solution  of  acetic 
acid,  while  watched  under  the  microscope,  in  consequence  of 
a  jarring  of  the  instrument,  became  broken  in  pieces,  and  the 
enamel-rods  isolated,  so  as  to  resemble  a  '  bunch  of  sticks.'  He 
asserts  that  '  this  method  will  perhaps  ultimately  be  the  means 

*  Dental  Cosmos,  1887. 


THE    MIXUTE    STRUCTrRE    OF    ENAMEL.  97 

of  throwing  some  light  on  tlie  matter  of  the  distribution  of 
lime-salts  and  living  matter  in  the  enamel,'  but  he  does  not,  so 
far  as  is  known,  follow  up  the  study. 

"The  method,  as  I  have  used  it,  is  as  follows:  A  freshly- 
extracted  tooth,  or  one  placed,  immediately  after  its  extraction, 
in  dilute  alcohol  for  a  time,  is  ground,  under  water,  as  thin  as 
practicable;  then  placed  in  a  six  per  cent,  solution  of  acetic 
acid,  and  left  there  for  at  least  twelve  hours  even  if  the  speci- 
men be  very  thin,  and  for  eighteen  hours  if  slightly  thicker ; 
the  acid  is  then  poured  off  and  the  specimen  repeatedly  washed 
with  distilled  water,  and  then  placed  in  a  concentrated  ammo- 
niacal  solution  of  carmin  for  twelve  hours.     After  its  removal 
from  the  carmin  solution  it  is  again  washed  with  distilled  water, 
and  the  enamel  detached  from  the  dentine  with  two  needles. 
This  process  is   easily  accomplished,  but  a  slight  frill  of  the 
organic  substance  of  the  enamel  is  usually  left  attached  to  the 
dentine,  and  we  obtain  the  enamel  itself  in  small  pieces.    I  have 
used-  two  other  reagents, — viz,  a  one-half  per  cent,  solution  of 
chloride  of  gold,  and  a  one  per  cent,  solution  of  hyperosmic 
acid.     The  specimens  are  subjected  to  the  action  of  the  former 
from  twelve  to  twenty  hours,  and  to  the  latter  from  one  to  three 
hours;   after   which   they  are    carefulh'  washed   with  distilled 
water;  then   treated   with   the    acetic-acid   solution   as   before 
stated.     They  are   again  washed;  then  mounted  in  glycerin, 
care  being  taken  that  they  are  not  broken  during  this  part  of 
the  process,  their  weakened  condition  from  the  action  of  the 
acetic  acid  having  rendered  them  very  brittle.     Such  a  speci- 
men, when  viewed  with  a  power  of  from  400  to  500  diameters, 
presents  the  following  features:  The  enamel-rods  are  plainly 
recognizable  (running  their  usual  way,  slightly  wavy  near  the 
dentine,  and  straight  toward  the  periphery),  owing  to  the  fact 
that  the  interstices  between  them  are  widened.   Another  feature 
presents  itself  which  is  quite  striking, — viz,  that  the  cross-bars 
within  the  enamel-rods  also  are  widened,  and  plainly  marked. 

"  We  often  meet  with  specimens  of  enamel  where,  toward  the 
dentine,  the  rods  are  entirely  lacking,  or  very  indistinct,  and 
much  narrower  than  those  a  little  distance  from  the  dentine. 
Should  the  bundles  of  rods  assume  a  fan-shaped  appearance,  as 
is  sometimes  seen  in  the  neighborhood  of  the  dentine,  the  inter- 
stices between  such  bundles  may' be  found  filled  with  a  granular 
material,  or  with  oblique  or  transverse  sections  of  rods,  occupj'- 

8 


98  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH, 

ing  comparatively  a  small  field.  This  latter  appearance  has 
undoubtedlj  led  previous  observers  to  conclude,  and  to  make 
the  statement,  that  the  enamel  is  composed  of  interlacing 
bundles  of  rods.  In  a  longitudinal  section  of  enamel  we  find 
comparatively  few  transversely-cut  bundles  of  rods,  whereas 
obliquely-cut  bundles  are  met  with  quite  frequently.  This  fact 
leads  to  the  conclusion  that  the  appearance  of  interlacing  is 
simply  due  to  the  presence  of  bundles  of  rods  running  in  a 
more  than  usually  wavy  course,  but  never  transversely  to  the 
general  direction  of  the  rods, 

"  The  manner  in  which  the  acetic  acid  acts  to  produce  the 
widening  of  the  interstices,  in  my  judgment,  is  as  follows  :  In  the 
process  of  grinding,  the  edges  or  borders  of  the  rods  are  more 
or  less  exposed  in  every  specimen,  and  probably  the  organic 
basis-substance  is  more  or  less  disturbed.  The  edges  being  thus 
exposed  to  the  action  of  the  acid,  the  same  as  the  ground  sur- 
faces of  the  rods,  are  dissolved  away,  and  the  interstices  become 
widened,  while  the  flat  surfaces  of  the  rods  themselves  are  not 
jierceptibly  afiected.  This  serves  to  explain  also  the  widening 
and  bringing  so  distinctly  to  view  the  '  cross-bars'  in  the  rods, 
which  also  contain  a  minute  amount  of  organic  matter.  Thin 
specimens  of  enamel .  treated  with  the  same  solution  of  acetic 
acid,  if  viewed  with  a  power  of  from  500  to  600  dia- 
meters, clearly  establish  the  above  facts,  since  we  can  invari- 
abl,y  trace  all  degrees  of  dissolution  of  lime-salts,  from  a  slight 
widening  of  the  interstices  to  the  coarse  granulation  of  the  rods, 
then  to  the  fine  granulation,  with  the  preservation  of  their 
general  appearance,  and  finally  down  to  their  complete  disap- 
pearance, nothing  being  left  but  the  organic  portion.  The 
appearance  in  the  field  of  the  microscope  is  now  very  striking, 
it  being  finely  granular,  pale,  and  traversed  by  innumerable 
parallel  filaments.  Even  moderately  thick  specimens  may  be 
utilized  for  bringing  to  view  completely  decalcified  fields,  by 
exerting  a  gentle  pressure  upon  the  covering-glass.  I  would 
not,  however,  recommend  broken  enamel-rods  for  microscopical 
research,  as  in  my  judgment  such  specimens  are  entirely  worth- 
less, I  prefer  to  confine  my  studies  to  shreds  in  which  either 
the  traces  of  the  previous  rods  are  recognizable,  or  the  fibers 
run  a  parallel  and  unbroken  course.  The  foregoing  description 
holds  good  for  the  majority  of  specimens  of  enamel.  There  are 
exceptions,    however.      Occasionally   we   find   specimens   with 


THE    .MINUTE    STRUCTURE    OF    EXAMEL. 


99 


Fig.  58. 


e^v\-' 


^,^ 


BEGI^M^u  Decalciiu ATiox  of  ExASfEL, 
Br  A  Six  Per  Cext.  Solution  of  Acetic 
Acid. 

The  interstices  between  the  enamel-rods  and 
the  cross-bars  of  the  rods  widened.  The  rods 
exhibit  slight  organic  structure,  in  consequence 
of  the  abundant  presence  of  lime.  Magnified 
500  diameters. 

Fig.  60. 


ExAMEL  Completely  Decalcified,  through 
THE  Agexct  of  a  Six  Per  Cent.  Solution 
OF  Acetic  Acid,  Slightlt  Staixed  with 
Chloride  of  Gold. 

The  upper  portion  of  the  figure  shows  slightly 
obliciue,  and  the  lower  very  oblique,  sections  of 
the  enamel-rods.  The  boundary  lines  of  the 
prisms  are  made  up  of  highly  glistening  elastic 
ledges,  at  the  sides  of  which  there  are  visible 
oblique  sections  of  enamel-fibers  in  connection 
with  a  delicate  grayish  reticulum  pervading 
the  rods.  This  reticulum  is  especially  dense  in 
the  central  portion  of  the  rods,  as  shown  in 
the  lower  half  of  the  figure.  Magnified  1200 
diameters. 


Advaxced  but  not  Complete  Decalcifica- 
tiox  of  Enamel,  through  the  agexct 
of  a  Six  Per  Cext.  Solutiox  of  Acetic 
Acid. 

The  interstices  very  marked,  but  not  mate- 
rially widened;  their  tenants,  the  enamel- 
fibers,  plainly  visible.  The  cross-bars  do  not 
appear  in  the  shape  of  interstices,  but  in  deli- 
cate transverse  lines.  The  organic  structure 
begins  to  appear,  owing  to  partial  removal 
of  the  lime-salts  by  solution.  Magnified  500 
diameters. 

Fig.  61. 


Completely  Decalcified  Enamel  Deeply 
Staixed  with  Chloride  of  Gold. 
The  enamel-fibers  appear  in  the  shape  of 
dark-violet,  beaded  threads,  in  connection  with 
a  grayish-blue  reticulum  within  the  enamel- 
rods.  The  transverse  threads  corresponding 
to  the  cross-bars  are  but  slightly  marked. 
In  the  lower  portion  of  the  figure  the  reticulum 
is  partly  torn  away,  leaving  the  enamel-fibers 
protruding  and  rendered  plainly  visible.  Mag- 
nified 1200  diameters. 


100  THE    ANATOMY    AND    rATHOLOGY    OF    THE    TEETH. 

unusually  narrow  prisms,  or  perhaps  lacking  them  altogether, 
in  comparatively  large  districts.  "Whether  this  feature  is  due  to 
advanced  age,  malformation,  or  some  pathological  condition,  I 
am  unable  to  say.  The  higher  powers  of  the  microscope  (1200 
to  1500  diameters)  ffive  a  hio-hlv  s-ratifving  imao;e  of  the  structure 
of  enamel.  Partially  decalcified  rods  appear  to  be  composed  of 
irregular  lumps,  of  high  refraction,  invariably  arranged  in  the 
shape  of  irregular  squares,  which  serve  to  complete  the  rods  ; 
the  irregular  interstices  separating  the  glossy  lumps  are  traversed 
by  delicate  grayish  threads.  The  interstices  causing  the  appear- 
ance of  cross-bars  through  the  rods  are  traversed  by  minute 
grayish,  beaded  filaments,  sending  oflshoots  into  the  fields  of 
the  rods  between  them.  The  longitudinal  interstices  between 
the  enamel-rods,  in  many  places,  show  long,  beaded  filaments, 
on  either  side  of  which  we  observe  a  light  space.  This  space 
again  is  traversed  by  conical  threads  arising  from  the  enamel- 
fibers,  and  penetrating  the  interior  of  the  rods  themselves. 

"  In  thoroughly  decalcified  enamel,  I  have  often  met  with  a  pe- 
culiar appearance.  "Whether  carmin,  chloride  of  gold,  or  osmic 
acid  hud  been  used  for  staining  the  specimen  is  immaterial, 
— the  rods  appear  to  be  surrounded  by  a  .glossy,  smooth,  or 
beaded  border,  between  which  can  be  seen  the  light  interstices. 
Sometimes  there  is  one  such  ledge  for  two  neighboring  rods, 
without  any  intervening  interstice.  In  oblique  sections  the 
ledges  are  best  marked  on  the  distal  portions  of  the  rods,  over- 
lapping their  neighbors  in  a  shingle-like  manner;  while  in 
transverse  sections  the  gloss}'  border  may  be  seen  all  around  the 
rods.  It  is  evident  that  these  ledges  cannot  be  mistaken  for  the 
enamel-fil)ers  proper;  nor  can  we  conclude  that  the  ledge  is  an 
optical  phenomenon,  caused,  as  it  were,  by  the  thickness  of  the 
rods,  since  the  ledge  is  often  found  slightly  protruding  beyond 
the  border  of  the  specimen.  The  only  explanation  I  can  sug- 
gest for  this  is  that  the  borders  of  the  rods  are  made  of  a  denser 
kind  of  basis-substance,  kindred  to  the  elastic  substance,  and 
similar  to  that  which  we  observe  in  the  basis-substance  of  the 
dentine  surrounding  the  canaliculi.  In  the  center  of  the  rod 
we  not  infrequently  see  a  somewhat  more  compact  accumulation 
of  a  pale  gray  substance  than  in  the  rest  of  the  rod. 

"  Completely  decalcified  portions  of  the  enamel  exhibit  a  most 
beautiful  reticulum,  especially  in  specimens  treated  with  chloride 
of  STold,  and  not  the  least  doubt  can  arise  as  to  the  fact  that  the 


THE    MIXUTE    STRUCTURE    OF    CEMEXTUM.  101 

enamel-fibers,  being  the  most  conspicuous  formations,  are  in  an 
uninterrupted  continuity  with  the  reticulum  of  living  matter 
pervading  the  whole  enamel." 


CHAPTER    XIL 

THE  MINUTE  STRUCTURE  OF  CEMENTUM.* 

The  zone  of  dentine  is  not  continuous  everywhere  about  the 
pulp-cavitv.  Around  the  apices  of  the  roots  the  cementum, 
although  the  outermost  layer  of  the  tooth,  immediately  lines  the 
cavity. 

In  the  cementum  delicate  parallel  striations  are  to  be  seen, 
identical  with  the  lamellae  of  a  Haversian  system,  and,  as  a  rule, 
more  plainly  marked  near  the  periphery  than  near  the  dentine. 
The  lamellae  exhibit  a  more  or  less  concentrical  arrangement 
around  the  pulp-cavity,  easily  demonstrable  on  cross-sections. 

Within  the  basis-substance  of  the  cementum  there  are  numer- 
ous branching  spaces,  in  correspondence  with  the  lacunie  of 
bone.  The  oiFshoots  of  these  spaces  in  the  cementum,  like  the 
spaces  themselves,  are  very  marked  in  dry  specimens,  because 
of  their  being  filled  with  air.  In  chromic-acid  specimens,  on 
the  contrary,  the  offshoots  are  much  less  prominent,  and  the  less 
so  the  more  thoroughh'  the  decalcification  has  been  effected  by 
the  acid.  jSTo  essential  difference  is  noticeable  in  the  lacunae 
and  canaliculi  of  ordinary  bone  from  those  of  the  cementum ;  in 
both  tissues  there  exists  great  variety  in  the  general  arrangement, 
in  the  size  of  the  lacunae,  and  in  the  number  and  ramifications 
of  their  offshoots. 

The  walls  of  the  lacunae  and  the  coarser  offshoots,  if  viewed 
with  a  highh^  magnifying  lens  (immersion  1000  to  1500  diam.), 
appear  interrupted  at  their  peripheries  by  light  openings,  which 
lead  into  a  light,  delicate  net-work,  piercing  the  whole  basis- 
substance  to  such  an  extent  that  the  meshes  have  to  be  con- 
sidered only  as  fields  of  calcified  glue-yielding  basis-substance. 

Each  lacuna  contains  a  protoplasmic  body,  with  a  central 
nucleus, — the    cement-corpuscle.      The   nucleus    sometimes    is 

*  • '  The  Distribution  of  Living  Matter  in  Human  Dentine.  Cement,  and  Enamel. ' ' 
Dental  Cosmos,  1878-1879. 


102  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

relatively  large,  and  surrounded  only  by  a  narrow  seam  of  proto- 
plasm ;  while  in  some  small  lacunae  a  body  of  the  appearance 
of  a  nucleus  is  present  without  a  noticeable  amount  of  surround- 
ing protoplasm.  The  net-like  structure  of  both  the  nuclei  and 
the  protoplasm  is  plainly  visible  in  all  cement-corpuscles.  From 
the  periphery  of  each  corpuscle  arise  conical  offshoots,  of  which 
the  coarser  ones  penetrate  into  the  larger  offshoots  of  the 
lacuna,  while  the  finest  offshoots  of  the  protoplasm  traverse  the 
light  rim  between  the  wall  of  the  lacnna  and  the  peripher}-  of 
the  jDrotoplasm,  being  directed  toward  a  light  interruption  on 
the  boundary  of  the  lacuna. 

Cement-corpuscles,  on  the  average,  are  round  or  spindle- 
shaped  bodies,  the  long  diameter  of  which  corresponds  to  the 
direction  of  the  lamellse.  In  the  teeth  of  juvenile  and  middle- 
aged  persons  we  meet  with  cement-corpuscles  three  or  four  times 
surpassing  the  size  of  ordinary  ones,  in  which  two  or  three 
nuclei  are  visible.  Instead  of  multinuclear  bodies,  a  number  of 
meclallary  nucleated  elements  may  fill  a  large  lacuna,  all  these 
elements  being  connected  with  one  another  by  very  delicate 
threads.  The  longitudinal  diameter  of  such  large  lacunae  is 
sometimes,  therefore,  an  axis  from  which  those  elements  radiate 
vertically  to  the  direction  of  the  lamella?. 

IN'umerous  cement-corpuscles  send  broad  and  branching  off- 
shoots through  the  basis-substance  in  a  direction  perpendicular 
or  oblique  to  the  lamellae,  and  not  infrequently  a  direct  union  is 
established  between  two  or  three  cement-corpuscles  by  means 
of  such  large  oftslioots.     (Fig.  42,  page  73.) 

In  some  teeth  broad,  spindle-shaped  spaces  pierce  the  ce- 
mentum  radiately,  all  of  them  containing  protoplasm  with  deli- 
cate oft'shoots  directed  toward  the  net-work  in  the  basis-substance. 
l!^ay,  sometimes  medullary  spaces  traverse  the  lamellfe  in  difi'er- 
ent  directions,  which  spaces  contain,  besides  a  varying  number 
of  medullary  elements,  capillary  blood-vessels  evidently  in  con- 
nection with  the  capillaries  of  the  pericementum.  These  forma- 
tions may  be  considered  as  remnants  of  the  embr^'onic  condition 
of  the  cementum,  and  are  never  present  in  large  numbers.  All 
protoplasmic  formations  within  the  cementum,  though  greatly 
varying  in  shape,  are  alike  in  being  connected  with  one  another 
by  the  delicate  net-work  that  pierces  the  basis-substance. 

At  the  periphery  of  the  cementum,  on  the  line  of  its  connec- 
tion with  the  pericementum,  the  net-work  of  the  protoplasm  is 


THE    MIXUTE    STRUCTURE    OF    CEMEXTUM.  103 

usually  veiy  broad,  and  the  fields  of  the  basis-substance  show 
a  prevailing  globular  appearance.  Also  numerous  spindle- 
shaped  protoplasmic  bodies  are  seen  in  connection  with  the 
cementum  in  an  oblique  arrangement,  forming  the  transition 
into  the  structure  of  the  pericementum.  Between  the  calcified 
cementum  and  the  striated  connective  tissue  of  the  pericementum 
there  often  exists  a  narrow  zone,  occupied  by  closely-packed 
spindle-shaped  protoplasmic  bodies  only.  In  the  pericementum 
itself  there  are  less   numerous,  partly  nucleated  protoplasmic 

Fig.  62. 


Teassition  of  Dextise  into  Cemextum,  tvithoct  a  Marked  Bouxdary. 

C,  branching  cement-corpuscle  ;  P,  spindle -shaped  cement-corpuscle  ;  both  in  direct  connec- 
tion with  dentinal  fibers,  F,  which  bifurcate  within  the  eanalieuli  of  the  dentine,  D.  Magni- 
fied 1200  diameters. 

bodies,  between  which  the  fields  of  an  apparently  homogeneous 
glue-yielding  substance  are  seen.     (See  Fig.  62.) 

The  connection  betAveen  dentine  and  cementum  is  established 
either  by  a  gradual  change  of  one  tissue  into  the  other,  without 
a  distinct  line  of  demarcation,  or  there  exists  a  boundary 
formed  by  a  more  or  less  marked  wavy  line,  presenting  irregu- 
lar bay-like  excavations.  Lastly,  it  occurs  that  between  the 
bay -like   excavations   and   the   dentine    there   is   interposed    a 


104  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

stratum  of  tlie  structure  of  cementum,  with  a  gradual  change 
of  the  tissue  of  the  former  into  that  of  the' latter.  (See  Fig.  63.) 
Where  a  gradual  change  takes  place,  the  dentinal  canaliculi 
show  irregular,  mainly  spindle-shaped  enlargements,  which  stand 
in  the  direction  of  the  dentinal  canaliculi  themselves,  or  run 
obliquely  through  the  basis-substance  of  the  cementum.  The 
distal  end  of  such  a  spindle  is,  as  a  rule,  in  connection  with  a 

Fig.  G3. 


\1 


E^^:;^ 


Teassitiox  of  De.ntixk  into  Cement,  with  an  Intermediate  Layer  of  Cement-stric- 
ture. 

U,  dentine ;  F,  bifurcating  dentine-fibers,  in  union  with  elongated  cement-corpuscles,  C^ ; 
these  are  imbedded  in  a  basis-substance  blending  with  that  of  dentine.  The  regular  cementum 
is  characterized  by  branching  corpuscles,  C-.    Magnified  1200  diameters. 

regular  lacuna  of  the  cementum,  or  with  an  analogous  forma- 
tion of  a  neighboring  dentinal  canaliculus.  Many  of  the  latter 
simply  pass  into  the  light,  delicate  net-work  characteristic  of  the 
basis-substance  of  cementum.  The  dentinal  fiber  is  in  direct 
union  with  the  protoplasm,  which  fills  the  spindle-shaped  spaces, 
or  it  is  lost  to  sight  upon  entering  the  net-work  of  the  basis- 
substance  of  the  cementum. 


THE    MINUTE    STRUCTURE    OF    CEMENTUM.  105 

Where  a  boundary  with  bay-like  excavations  is  present  be- 
tween dentine  and  cementum,  spindle-shaped  enlargements  of 
the  dentinal  canaliculi  may  be  seen,  much  smaller  than  in  the 
former  instance.  The  majority  of  the  dentinal  canaliculi, 
however,  reach  the  boundary  of  the  cementum  after  repeated 
bifurcations,  by  which  the  caliber  both  of  the  canaliculi  and 
of  their  central  fibers  is  gradually  diminished. 

A  connection  of  the  dentinal  fibers  with  the  coarser  oflishoots 
of  the  cement-corpuscles  is  often  observed.  The  light  net-work 
of  the  basis-substance  of  the  dentine  always  passes  into  that  of 
the  cementum.  ^IsTot  rarely,  also,  on  the  bottom  of  a  bay-like 
excavation,  partly  nucleated  protoplasmic  bodies  are  present, 
into  which  the  dentinal  fibers  inosculate.  The  connection 
between  these  and  the  coarser  oftshoots  of  the  cement-cor- 
puscles under  these  circumstances  is  established  by  such  inter- 
vening protoplasmic  bodies. 

The  Neck  of  the  Tooth. — There  are  certain  peculiarities  about 
the  minute  anatomy  of  the  neck  of  the  human  tooth  which,  so 
far  as  I  can  judge  from  the  literature  within  my  reach,  have  not 
heretofore  been  mentioned. 

John  Tomes*  in  describing  the  distribution  of  the  dentinal 
tubes,  says,  "Near  the  neck  they  stop  short  of  the  cementum." 

This  assertion  is  in  accord  with  the  v^a-iter's  observations. 
In  the  great  majority  of  teeth  neither  the  canaliculi  nor  their 
tenants,  the  dentinal  fibers,  reach  that  part  of  the  cementum 
which  surrounds  the  neck.  I^ear  the  periphery  of  the  dentine 
bifurcations  of  the  canaliculi — and  consequently  also  of  their 
tenants,  the  dentinal  fibers — take  place,  some  of  the  finest  ter- 
minations of  which  run  to  the  boundary  between  the  dentine 
and  cementum.  As  a  rule  the  finest  terminations  of  these 
fibers  are  lost  to  sight  in  a  net-work  somewhat  coarser  than  that 
of  the  basis-substance  of  ordinary  dentine.  The  minute  elonga- 
tions of  the  dentinal  fibers  can  also  be  traced  into  the  light  net- 
work with  more  distinctness  than  elsewhere  in  the  dentine. 
Sometimes  the  dentinal  canaliculi,  upon  approaching  the  periph- 
ery, become  slightly  dilated  so  as  to  produce  slender  pear-shaped 
cavities,  in  accordance  with  which  the  terminating  dentinal 
fibers  exhibit  slight  enlargements. 

The  boundary  between  dentine  and  cementum  presents  a 
wavy  line,  traversed  by  delicate  threads,  or  occupied  by  spindle- 

*  "  System  of  Dental  Surgery,"  1873. 


106  THE    AXAT03IY    A^'D    PATHOLOGY    OF    THE    TEETH. 

shaped  protoplasmic  formations,  all  of  which  are  in  union  with 
direct  or  indirect  elongations  of  the  dentinal  fibers. 

The  cementum  around  the  neck  forms  a  narrow  layer,  which 
is  cut  ofi"  obliquely  at  the  place  of  junction  with  the  enamel. 
Both  the  cementum  and  enamel  in  this  situation — being  of  the 
same  width — are  separated  by  a  boundary  w^hich  runs  from  the 
outer  periphery  obliquely  downward  to  the  dentine.  This  rela- 
tion I  found  in  the  majority  of  teeth,  and  it  is  only  exception- 
ally that  I  have  met  with  cementum  regularly  overlapping  the 
enamel.  The  cementum  on  the  neck  is  built  up  of  delicate 
prisms,  or  spindles,  arranged  verticallj^  to  the  surface  of  the 
dentine.  The  prisms  represent  the  fields  of  the  basis-substance, 
and  are  separated  from  one  another  by  light  rims,  holding  beaded 
fibers,  or  traversed  by  delicate  vertical  threads.  In  transverse 
sections,  when  the  prisms  are  cut  obliquely,  they  exhibit  irregu- 
lar opaque  fields  separated  from  one  another  by  light  rims. 

These  formations  closely  resemble  the  protoplasmic  bodies 
of  the  pericementum  next  to  the  cementum,  alluded  to  in  the 
former  chapter ;  hence  I  do  not  hesitate  to  consider  the  bony 
formation  on  the  neck  as  being  produced  by  calcification  of  the 
osteoblasts  of  the  pericementum.  The  cementum  on  the  neck 
of  the  tooth  is  devoid  of  lamellae  and  lacunae,  which  appear 
deeper  below,  together  with  all  the  characteristic  features  of  the 
fully-developed  structure  of  the  cementum.  The  lamellae 
become  the  more  distinct,  and  the  lacuna,  with  their  contents 
(the  cement-corpuscles),  the  more  numerous,  the  broader  the 
diameter  of  the  layer  of  the  cementum. 

The  outer  surface  of  the  cementum  is  covered  on  its  upper 
part  with  epithelial  elements  closely  resembling  those  of  jSTas- 
myth's  layer  of  the  enamel.  This  layer  turns  over  into  the 
epithelial  coat  of  the  gum.  Farther  down,  the  cementum, 
though  still  endowed  with  properties  characteristic  of  the  neck 
of  the  tooth,  is  surrounded  by  the  fibrous  connective  tissue  of 
the  pericementum. 

I  have  met  in  one  instance  with  striking  formations  on  the 
neck  of  a  tooth,  which  I  consider  anomalous,  but  not  quite 
pathological.  Here  the  ordinary  cement  of  the  neck  is  inter- 
rupted by  grooves  or  pits  containing  the  elements  of  perice- 
mental tissue.  The  inner  periphery  of  the  pit  is  covered  with 
a  well-developed,  evidently  isolated  formation  of  cementum. 
The  island  of  the  cementum  is  broadest  above  the  bottom  of  the 


THE    MIXUTE    STRUCTURE    OF    CE.MEXTUM,  107 

pit,  and  slopes  down  along  tlie  walls  of  the  pit,  until  it  is  lost 
within  the  layer  of  the  cementum  of  the  neck.     (See  Fig.  64.) 

Results.— -The  cementum,  as  well  as  ordinary  bone,  is  provided 
with  lacunfe  and  canaliculi.  The  lacunas  contain  nucleated  proto- 
plasmic bodies,  and  the  canaliculi  hold  offshoots  of  the  living 
matter  of  the  protoplasm.  The  whole  basis-substance  of  the 
cementum  is  traversed  by  a  delicate  net-Avork,  which  in  all  pro- 
bability contains  living  matter,  though  this  is  traceable  only  in 

Fig.  64. 


^   ^-    ''  -    ^  ■■    ^.,;  V  \-?i 


\ 


1 


K. 


-—d:b 


Anomalous  Foematiox  of  Cementu.vi  ox  the  Xeck  of  a  Hcmax  Tooth. 

B,  dentine;  DF,  dentinal  fibrillfe;  JV,  cementum  on  neck  of  tooth,  with  spindle-shaped 
or  prismatic  fields  of  basis-substance  ;  DP,  depression  in  the  cementum  of  the  neck,  filled  with 
elementsof  pericementum  surrounded  superiorly  by  a  zone  of  regularly  developed  cementum,  C; 
P,  pericementum.    Magnified  1200  diameters. 

its  thorn-like  projections  from  the  periphery  of  the  protoplasm 
and  its  larger  offshoots.  The  living  matter  of  the  cementum 
is  uninterruptedly  connected  with  that  of  the  periosteum,  and 
continuous  with  the  living  matter  of  the  dentine,  either  through 
intervening  protoplasmic  bodies  in  the  interzonal  layer,  or 
directly  with  the  dentinal  fibers. 

The  cementum  covering  the  neck  of  the  tooth  is  devoid  of 
lamellae  and  protoplasmic  bodies.  It  is  built  up  of  directly  calci- 
fied osteoblasts  of  the  pericementum,  presenting  their  prismatic 
shapes,  and  everywhere  traversed  by  a  net-work  of  living  matter. 


108  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

This  is  ill  connection  either  with  the  epithelium  of  i^Tasmyth's 
layer  or  the  pericementum,  and  with  the  dentine  mainly  through 
the  intervening  net-work  in  the  basis-substance  of  the  latter. 

Investigations  concerning  the  structure  of  the  cementum  have 
been  published  by  Carl  Heitzmann  and  F.  A.  Roy,*  of  which  I 
otter  the  following : 

"  Method. — A  recommendable  method  for  the  study  of  the 
microscopical  structure  of  the  cementum  is  to  grind  a  tooth  as 
thin  as  possible,  always  keeping  it  moist  with  a  one  per  cent, 
solution  of  table-salt.  First,  with  a  fine  saw  or  with  a  corundum - 
stone  in  the  lathe,  a  coarse  slab  is  made  of  the  freshly-extracted 
tooth,  which  afterward  is  ground  thin  on  a  corundum-slab,  and 
finished  on  an  Arkansas  stone.  The  specimen  is  not  allowed  to 
become  dry  for  a  moment.  After  brushing  away  the  debris  from 
grinding,  the  specimen  is  directly  mounted  in  chemically-pure 
glycerin,  or  staining  with  ammoniacal  carmin  may  be  resorted 
to,  though  such  a  stain  is  of  comparative!}'  little  value  in  the  study 
of  cementum.  Some  of  our  illustrations  are  made  from  specimens 
prepared  in  the  manner  just  described.  The}'  are  especially 
plain  when  examined  immediately  after  mounting,  but  rarely  fit 
for  higher  powers  of  the  microscope, — powers  exceeding  from 
500  to  600  diameters.  After  several  weeks,  when  the  glycerin 
has  thoroughly  saturated  the  specimen,  the  minute  features  are, 
as  a  rule,  less  conspicuous  than  in  the  freshly-mounted  specimen. 

"  The  method  first  employed  by  William  Carr,  in  1889,  for 
bringing  to  view  the  minutest  structure  of  the  dentine,  is  a  pro- 
tracted stain  with  a  one-half  of  one  per  cent,  solution  of  chloride 
of  gold,  of  plates  ground  thin  with  the  finger  on  grinding-stones 
and  corundum-slabs,  and  a  subsequent  complete  decalcification 
by  means  of  a  six  per  cent,  solution  of  glacial  acetic  acid.  This 
method  has  also  enabled  John  I.  Hart  to  obtain  perfect  speci- 
mens of  dentine.  The  same  procedure  we  have  adopted  for 
clearing  up  the  minutest  features  in  the  structure  of  the  ce- 
mentum. Freshly-extracted  teeth  are  placed  in  a  one  per  cent, 
solution  of  talile-salt  and  ground  thin,  as  before  stated.  It  is 
important  to  leave  the  extracted  teeth  a  short  time  only  in  the 
salt  solution, — a  few  hours  at  the  utmost, — since  the  protoplas- 
mic formations  of  the  cementum  become  hydropic  and  unstain- 
able  with  chloride  of  gold  if  left  in  the  solution  for  days.     This 

*  Transactions  of  the  New  York  Odontological  Society,  1892. 


THE    MINUTE    STRUCTURE    OF    CE.MENTUM.  109 

tissue,  being  directly  exposed  to  the  salt  solution,  is  altected  by 
it  sooner  than  the  dentine.  Special  care  must  betaken  in  keep- 
ing the  slabs  moist  ^Yith  a  weak  solution  of  table-salt,  lest  the 
specimen  become  dry,  and  the  lacune?  and  the  coarser  canaliculi 
filled  with  air,  by  which  the  details  are  rendered  indistinct,  or 
obliterated  completely.  After  the  slab — immaterial  whether  a 
longitudinal  or  a  transverse  section — has  attained  a  sufficient 
degree  of  thinness,  as  proven  by  mounting  on  a  slide  and  cover- 
ing with  the  thinnest  possible  covering-glass,  it  must  be  washed 
carefully  and  repeatedly  with  a  camel's-hair  brush,  under  con- 
tinuous renewal  of  the  salt  solution.  Xext  the  slab  is  placed  in 
a  one-half  of  one  per  cent,  solution  of  chloride  of  gold,  in  which 
process  all  metallic  instruments  must  be  avoided,  the  simplest 
spatula  being  a  match  shaped  with  a  penknife.  If  several  sec- 
tions should  be  ready  for  treatment  with  chloride  of  gold,  it  is 
necessary  to  see  that  each  one  be  in  free  contact  with  the  gold 
solution.  Specimens  overlapping  one  another  prevent  a  perfect 
stain,  because  they  will  not  allow  the  desired  contact  and  pene- 
tration with  the  gold  solution." 

"  The  time  required  for  exposure  to  the  gold-salt  is  somewhat 
different  with  different  teeth,  probably  because  of  the  variable 
amount  of  lime-salts  infiltrating  the  cementum.  The  best  re- 
sults we  have  obtained  were  on  temporary  teeth  left  in  the  gold 
solution  from  six  to  seven  hours, — certainly  a  shorter  time  than 
is  required  for  staining  the  dentine.  The  following  exposure 
for  ten  hours  to  a  six  per  cent,  solution  of  glacial  acetic  acid  is, 
as  a  rule,  sufficient  for  complete  decalcification  of  the  cementum, 
and  now  the  specimen  may  be  exposed  to  broad  daylight  for  a 
number  of  days,  until  it  has  assumed  a  dark-violet  or  dark- 
purple  color.  The  only  precaution  required  at  this  stage  of  the 
procedure  is  to  renew  every  day  the  distilled  water  in  which 
the  specimen  lies,  in  order  to  prevent  the  growth  of  mildew. 
A  drop  of  chemically-pure  glycerin  added  to  the  distilled  water 
is  a  sure  means  of  keeping  away  the  mildew.  The  mounting  of 
such  specimens  is  invariably  done  in  glycerin, — the  only  medium 
which  allows  the  examination  with  the  highest  powers  of  the 
microscope. 

"  We  admit  that  the  results  obtained  in  the  described  manner 
of  treating  cementum  were  not  uniformly  satisfactory,  in  contra- 
distinction to  those  in  the  preparation  of  dentine,  in  which  failures 
are  exceptional.     We  cannot  account  for  the  fact  that  specimens 


110  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

of  difterent  teeth  which  we  knew  to  be  alive  and  perfectly  fresh, 
yielded  good  images  only  occasionally.  Cohnheim,  the  dis- 
coverer of  the  gold-stain,  met  with  the  same  accidents.  Some- 
times the  basis-substance  assumes  a  deeper  color  than  the  con- 
tents of  the  lacunae ;  the  latter  may  remain  so  pale  even  as  to 
imitate  features  of  devitalized  teeth.  Specimens  well  stained, 
however,  exhibited  all  features  so  handsomely  that  we  thought 
best  to  describe  this  method,  leaving  the  invention  of  new  pro- 
cedures to  other  observers.  It  is  especially  the  acetic  acid  which 
we  suspect  of  yielding  unsatisfactory  results,  and  other  acids — 
perhaps  diluted  sulphuric  acid — may  have  to  be  resorted  to  in 
future  trials.  Owing  to  the  unequal  efficiency  of  the  method 
employed,  we  will  abstain  from  statements  which  are  of  the 
utmost  importance  to  the  practitioner, — viz,  the  definition  of  the 
living  from  the  non-living  part  of  the  cementum  in  pulpless 
teeth.  The  results  of  our  examination  seem  to  be  sufficiently 
interesting,  however,  so  far  as  they  go,  to  deserve  presentation. 

"  Cement  of  the  Roots. — We  have  examined  quite  a  number 
of  roots  of  teeth,  both  deciduous  and  permanent,  in  specimens 
ground  thin  under  the  protection  of  an  indiflierent  liquid, — a  one 
per  cent,  solution  of  table-salt.  Our  intention  has  been  to  study 
the  features  of  the  cement-tissue  in  freshly-ground  specimens, 
before  they  were  exposed  to  the  influence  of  a  solution  of 
chloride  of  gold.  What  we  saw  in  many  instances  has  not  up 
to  this  time  been  described.     (See  Fig.  65.) 

"  With  low  powers  of  the  microscope,  we  find  on  the  surface 
of  the  cementum  shallow  pits  that  render  the  border-line,  in  a 
longitudinal  section,  hilly  or  wavy.  This  corresponds  to  the 
rough,  slightly-pitted  aspect  of  the  surface  of  the  roots,  viewed 
with  the  naked  eye.  The  lamellated  portion  of  the  cement 
tapers  toward  the  neck  of  the  tooth,  and  becomes  the  broader 
as  it  approaches  the  apices  of  the  roots.  In  this  portion  of  the 
cement-tissue  the  parallel  lamellae  are  conspicuous,  and  we  notice 
scattered  in  the  basis-substance  a  number  of  cement-corpuscles 
which  differ  from  ordinary  bone-corpuscles  only  in  being  more 
irregular,  often  elongated,  apparently  arranged  without  regu- 
larity, certainly  without  parallelism  to  the  lamellse.  Besides  the 
cement-corpuscles,  we  notice  a  number  of  lines  running  from 
the  surface  to  the  dentine,  and  piercing  the  lamella?  at  right  or 
acute  angles,  often  in  union  with  the  cement-corpuscles.  The 
course  taken  by  these  lines,  which  in  their  parallelism  bear 


THE    3IIXUTE    STRUCTURE    OF    CEMEXTUM. 


Ill 


somewhat  the  aspect  of  dentinal  fibers,  is  always  devious  from 
the  latter,  with  which  they  produce  obtuse  angles.  We  have 
failed  to  find  an  immediate  union  of  dentinal  fibers  with  the 
fibers  pierciug  the  cementum.  The  lamellated  portion  is  fol- 
lowed by  a  layer,  indistinctly  lamellated  or  striated,  likewise  con- 
taining cement-corpuscles,  and  likewise  traversed  b}'  radiating 
lines.  This  layer,  either  indistinctly  lamellated  or  entirely 
destitute  of  lamellae,  we  propose  to  term  '  the  osteoid  la;yer  of 
the  cementum.'     At  the  boundary  of  the  osteoid  layer,  toward 

Fig.  65. 


Root  of   a  Ground  Bicuspid,  showixg  a  Combixatios  of  Lamellated  axd  Osteoid 

Cemextum, 
P,  pericementum;  T,  thickness  of  the  specimen;  L,  lamellated  cementum;  0.  osteoid  ce- 
mentum;  Z,  interzonal  layer  between  cementum  and  dentine:   D,  dentine.    Magnified  200 
diameters. 

the  dentine,  a  layer  of  numerous  small  protoplasmic  bodies  is 
seen  in  our  specimen,  similar  to  those  of  an  ill-calcified  enamel, 
and  probably  due  to  a  deficient  calcification  of  the  cementum. 
This  layer  is  rather  exceptional.  The  dentinal  canaliculi  either 
stop  short  of  the  interzonal  osteoid  laj^er,  or  a  limited  number 
of  canaliculi  is  seen  to  directly  run  into  the  interzonal  layer, 
where  they  inosculate  with  the  coarse  protoplasmic  reticulum. 
"  The  aspect  of  the  cement-corpuscles  in  the  distinctly  lamel- 


112 


THE    AXAT03IY    AND    rATHOLOGY    OF    THE    TEETH. 


lated  portion  is  rather  peculiar  in  ground  specimens,  mounted 
in  glycerin,  when  viewed  with  medium  powers  of  the  micro- 
scope, 500  to  600  diameters.  The  lacuna  appear  filled  with 
protoplasmic  bodies,  in  the  center  of  which  we  notice  oblong 
nuclei.  From  the  periphery  of  the  bodies  numerous  offshoots 
break  forth,  which  either  directly  connect  neighboring  cement- 
corpuscles,  or  are  lost  in  the  basis-substance.  Innumerable  fine 
oftshoots  are  seen  to  emanate  from  the  coarse  ones,  and  by 

Fig.  66. 


Lamellated  Cemextum  of  the  Root  of  a  Ground  Bicuspid. 

C,  C,  cement-corpuscles  branching  and  interconnecting;  R,  incomplete  reticulum,  produced 
by  the  finest  offshoots  of  the  cement-corpuscles  ;"X,'X,  boundary-lines  of  the  lamellae.  Mag- 
nified 600  diameters. 

these  finest  ofishoots  an  indistinct  net-work  is  established,  par- 
ticularly plain  in  the  vicinity  of  the  cement-corpuscles.  The 
basis-substance  appears  coarsely  granular,  but  no  reticulum 
proper  can  be  made  out  with  this  amplification.  The  basis- 
substance  is  pierced  by  peculiar  fibers  which  intersect  the 
lamellae  at  right  or  acute  angles,  often  are  bifurcate,  and  in 
many  instances  are  independent  of  the  cement-corpuscles  or 
their  ofl:shoots,  while  in  other  instances  they  distinctly  inoscu- 
late with  the  two  last-named  formations.     (See  Fig.  QQ.) 


THE    MINUTE    STRUCTURE    OF    CEMENTUM.  113 

"  The  question  arises,  AVhat  are  these  fibers  iu  the  cementura  ? 
The  first  idea  suggesting  itself  is  that  we  have  to  deal  with  per- 
forating fibers,  first  described  by  Sharpey  in  specimens  of  dry 
bone-tissue.  Charles  S.  Tomes*  says,  'Like  bone,  cementum 
is  also  sometimes  found  to  contain  Sharpey's  fibers ;  that  is  to 
say,  rods  running  through  it  at  right  angles  to  its  own  lamina- 
tion, and,  as  it  were,  perforating  it.  These  are  probably  calcified 
bundles  of  connective  tissue.' 

"  Sharpey's  fibers  are  never  seen  in  specimens  decalcified  by 
solutions  of  chromic  acid.  Histologists  assert  that  they  are 
elastic  fibers,  not  perishable  after  treatment  of  the  specimen 
with  caustic  potash.  The  fibers  in  the  cementum,  on  the  con- 
trary, are  caualiculi  in  the  basis-substance,  holding  protoplasm, 
or  rather  living  matter,  which  feature  renders  them  akin  to 
dentinal  fibers.  AVe  propose  the  name  of  '  piercing  cement- 
fibrillai'  for  their  designation. 

"  The  ultimate  analysis  of  the  tissue  of  cementum  is  possible 
only  after  exposure  to  a  solution  of  chloride  of  gold  and  subse- 
quent decalcification  with  acetic  acid.     (See  Fig.  67.) 

"  TVe  see  the  cement-corpuscles,  the  nuclei  of  which  often 
appear  a  trifie  lighter  than  the  rest  of  the  protoplasm.  The 
reticular  structure  of  the  latter  is  plain  in  many  corpuscles. 
Xumerous  coarse  and  innumerable  fine  oft'shoots  break  forth 
from  the  periphery  of  the  cement-corpuscles.  Close  around 
the  latter  and  their  coarse  offshoots  a  light  rim  is  present,  tra- 
versed by  the  minutest  conical  oft'shoots,  Avhich  rim  obviously 
corresponds  to  the  wall  of  the  lacunse  and  canaliculi.  The  walls 
are  rendered  indistinct  by  the  decalcification  of  the  specimen. 
The  whole  basis-substance  is  traversed  by  an  extremely  minute 
reticulum  of  a  dark-violet  color,  interconnecting  all  cement- 
corpuscles.  The  behavior  of  this  reticulum  toward  chloride  of 
gold  clears  up  the  nature  of  it :  living  matter  produces  the  net- 
work in  the  protoplasm,  as  well  as  in  the  basis-substance.  Of 
this  reticulum,  however,  the  meshes  must  be  considered  as  the 
basis-substance  proper,  composed  of  what  we  term  glue  or  gela- 
tin, and  saturated  with  lime-salts.  The  boundary  zone  or 
interzonal  layer  between  dentine  and  cementum  is  conspicuous 
by  its  bay-like  excavations.  In  this  region  we  easily  recognize 
the  union  of  most  of  the  dentinal  fibers  with  coarser  offshoots 

'■A  Manual  of  Dental  Anatomy.'"     PhiladelpMa,  1876. 
9 


114 


THE    ANATOJIY    AND    PATHOLOGY    OF    THE    TEETH, 


of  the  eement-eorpiiscles, — a  fact  already  established  by  Bo- 
decker.  An  immediate  union  of  the  living  matter  of  the  den- 
tine with  that  of  the  cementum  is  fairly  plain,  since  from  six  to 
eight  hours'  exposure  to  the  solution  of  chloride  of  gold  was 
sufficient  to  bring  to  view  the  reticulum  in  the  cementum, 
whereas  ten  hours'  exposure  is  needed,  accordmg  to  John  I. 
Hart,  to  stain  the  reticulum  of  the  dentine  to  a  satisfactory 
degree.     jSTo  doubt,  in  a  living  tooth,  the  whole  cementum  is  a 


Fig.  67. 


Root  of  a  Molae  in  Loxgitudixal  Section.    Stained  -nrrH  Chloride  op  Gold. 

P,  nucleated  protoplasmic  body  with  coarse,  dark -violet  ofiFshoot?;  C,  basis-substance  of  ce- 
mentum, pierced  by  a  violet  delicate  reticulum;  i>,  D.  dentine.  Most  of  the  dentinal  fibers 
unite  with  offshoots  of  cement-corpuscles.    Magnified  12C0  diameters. 

tissue,  endowed  with  properties  of  life,  the  same  as  is  dentine. 
Life  is  not  conlined  to  the  cement-corpuscles  and  their  coarser 
otishoots,  but  extends  all  through  the  basis-substance,  being 
active  within  the  reticulum  that  pervades  the  protoplasm  ;  and 
active  also  within  that  of  the  basis-substance.  The  study  of  the 
pathology  of  cementum  has  furnished  ample  proof  for  the  cor- 
roboration of  this  statement. 
"  Osteoid  Cementum. — The  tissue  of  the  cementum  covering 


THE    MINUTE    STRUCTURE    OF    CEMENTUM. 


115 


the  neck  of  the  tooth  is  diit'erent  in  its  microscopical  structure 
from  the  main  mass  of  the  cementum.  It  is  known  that  the 
thin  layer  of  this  tissue  gradually  blends  with  the  cementum 
proper.  First  the  prisms  of  the  neck-layer  disappear,  and  a 
granular  layer  makes  its  appearance,  destitute,  as  yet,  of  lamellae 
and  cemeut-corpuscles,  exhibiting  a  few  faint  striations,  and  tra- 
versed, as  in  our  specimen,  occasionally,  though  not  always,  by 
piercing  cement-librills?.     (See  Fig.  68.) 

"  This    formation    is    probably    what    Charles    S.    Tomes* 


Rout  of  a  Ground  Bicuspid  ix  Loxgitudixal  Sectiox.    Traxsitiox  of  the  Cemextum 
OF  THE  Neck  ixto  that  of  the  Root. 
P,  pericementum  :   T,  thickness  of  the  specimen  :  0,  osteoid  layer  of  the  cementum;  D,  den- 
tine ;  L,  protoplasmic  bodies  at  the  interzonal  layer  between  dentine  and  cementum.    Magnified 
200  diameters. 

describes  in  the  following  words  :  '  The  matrix  of  the  cementum 
is  sometimes  apparently  structureless,  at  others  finely  granular 
or  interspersed  with  small  globules.'  We  wish  to  term  it  the 
'  osteoid  layer'  of  the  cementum.  By  the  name  'osteoid'  the 
histologists  designate  a  tissue  kindred  to  bone,  saturated  with 
lime-salts,  lacking  bone-corpuscles  or  showing  but  few  of  them, 
and  without  lamella?.  All  this  characterization  holds  good  for 
the  portion  of  the  cementum  under  consideration.     Its  history 

*  "  A  Manual  of  Dental  Anatomy. ' "     Philadelphia,  1876. 


116 


THE    ANATOMY    AND    PATHOLOGY    OF   THE    TEETH. 


of  development  will  be  cleared  up  some  day,  when  the  develop- 
ment of  eementum  will  be  studied  in  human  teeth, — a  study  not 
as  yet  accomplished. 

"  The  osteoid  layer  shows,  as  it  nears  the  lamellated  eementum, 
a  few  irregular  bone-corpuscles.  The  lamellated  portion  starts 
from  the  periphery  of  the  root,  and  soon  becomes  broader  and 
supplied  with  regular,  freely-branching  cement-corpuscles,  with 
the  result  that  the  osteoid  structure,  in  the  majority  of  the  teeth 
examined,  is  lost  to  sight.     In  the  specimen  from  which  the 

Fig.  69. 


KooT   OF  A  Geousd   Molar  in   Longitudinal  Section.    Transition   of  Osteoid  into 
Lamellated  Cementum. 

P,  pericementum  ;  T,  thickness  of  the  specimen  ;  X,  lamellated  eementum ;  0,  osteoid  ee- 
mentum ;  Z,  interzonal  layer  between  dentine  and  eementum;  D,  dentine.  Magnified  200 
diameters. 

illastration  is  taken,  the  dentinal  iibrill?e  stop  short  of  the 
osteoid  layer,  a  feature  so  characteristic  of  the  anatomy  of  the 
neck.  ISTear  the  interzonal  layer,  between  the  dentine  and  the 
osteoid  tissue,  a  few  small  protoplasmic  bodies  are  seen,  into 
which  dentinal  fibers  inosculate. 

"  ISTot  infrequently  the  osteoid  layer  does  not  perish,  even 
though  lamellated  eementum  has  made  its  appearance  ;  nay,  the 
osteoid  layer  may  be  seen  all  around  the  root,  as  an  intervening 
formation  between  dentine  and  eementum.     Fie;.  69  is  taken 


THE    MINUTE    STRUCTURE    OF    CEMENTUM.  117 

from  sucli  a  specimen.  Here  we  see  the  beginning  of  a  lamel- 
lated  formation,  between  which  and  the  dentine  are  protoplasmic 
bodies,  with  a  number  of  long  and  parallel  offshoots,  of  the 
aspect  of  piercing  fibers.  The  interzonal  layer,  in  this  instance, 
is  conspicuous  by  a  large  number  of  interconnecting  protoplas- 
mic bodies,  in  union  on  their  upward  course  with  cement- 
corpuscles,  and  on  their  downward  course  with  dentinal  fibers. 
This  peculiar  formation  is  traceable  all  along  the  roots,  and 
signifies  an  incomplete  deposition  of  lime-salts  at  the  time  of 

Fig.   70. 

p 


Osteoid  Layer  of  the  Root  of  an   Incisor.    L(jngitudinal  Section.    Stained   with 

Chloride  of  Gold. 

P,  protoplasmic  body,  with  scanty,  coarse  oifshoots;  0,  coarse  oifslioot,  apparently  in  no  con- 
nection with  a  protoplasmic  body  ;  B,  basis-substance  of  the  osteoid  layer,  traversed  by  a  deli- 
cate reticulum.    Magnified  1200  diameters. 

the  formation  of  the  cementum.  The  dentine  of  this  tooth  is 
fully  developed,  lacking  even  the  so-called  interglobular  spaces 
in  the  crown. 

"  In  order  more  thoroughly  to  understand  the  structure  of  the 
osteoid  layer,  we  have  applied  to  such  specimens  the  protracted 
gold  stain,  with  subsequent  decalcification  by  means  of  diluted 
acetic  acid ;  the  image  thus  obtained  was  a  striking  one  indeed. 
(See  Fig.  70.) 


118 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


"  We  observe  small,  odd-sliaped  protoplasmic  bodies  of  a  dark- 
violet  color,  exhibiting  but  a  limited  number  of  coarse  oftshoots. 
Besides,  coarse  dark-violet  fibers  traverse  the  basis-substance, 
making  a  coarse  net-work,  arranged  without  apparent  regular- 
ity, and  also,  as  it  seems,  lacking  connections  with  larger  proto- 
plasmic masses.  This  latter  feature  may  be  due  to  a  curved 
course  of  the  fibers,  the  union  with  cement-corpuscles  being 
severed  by  the  process  of  grinding.  The  whole  basis-substance 
is  seen  to  be  traversed  by  a,  comparatively  speaking,  coarse, 
dark-violet  reticulum,  in  union  with  the  protoplasmic  bodies,  as 

Fig.  71. 


Osteoid  Cementum  op  the  Root  op  a  Ground  Bicuspid. 

C,  osteoid  layer  of  the  cementum,  with  scanty  protoplasmic  bodies  and  piercing  cement- 
fibrillas ;  Z,  interzonal  layer  between  dentine  and  cementum,  with  numerous  branching  proto- 
plasmic formations  ;  B,  dentine  with  scanty  protoplasmic  bodies.    Magnified  600  diameters. 


well  as  with  the  coarse  fibers.  Unquestionably  the  reticulum  is 
the  living  matter  proper,  which  endows  the  osteoid  layer  with  a 
considerable  degree  of  vitality  and  sensibility. 

"  The  peculiar  interzonal  formations,  represented  in  Fig.  69, 
we  have  also  examined  with  higher  powers  of  the  microscope. 
(See  Fig.  71.) 

"  We  notice  small  protoplasmic  bodies  branching  and  inter- 
connecting. Upward  their  offshoots  run  into  cement-corpuscles, 
or  into  piercing  fibers  of  the  cementum,  whereas,  downward  the 
oftshoots  blend  with  the  dentinal  fibers.     Even  the  dentine  is 


THE    MINUTE    STRUCTURE    OF    CEMENTUM.  119 

possessed  of  protoplasmic  formations,  a  certain  distance  away 
from  the  interzonal  layer;  all  of  which  proves  a  deficient  calci- 
fication just  at  the  time  of  the  beginning  of  the  development  of 
the  cementum.  The  specimen  from  which  the  drawing  is  made 
was  not  stained  with  chloride  of  gold,  and  not  decalcified ;  hence 
the  reticulum  of  the  basis-substance  is  only  indicated,  not  con- 
spicuous.    A^o  doubt,  however,  can  arise  about  its  presence. 

"  Cementum  of  the  Neck. — Bodecker  was  the  first  to  accurately 
describe  the  minute  anatomical  features  of  the  cementum  of 
the  neck.  How  defective  the  knowledge  of  this  region  was, 
even  sixteen  years  ago,  is  best  shown  by  a  quotation  from 
Charles  S.  Tomes,  who  says,*  '  Where  the  cementum  is  very 
thin,  as,  for  instance,  where  it  commences  at  the  neck  of  a 
human  tooth,  it  is  to  all  appearance  structureless,  and  does  not 
contain  any  lacuna?.'  The  cementum  of  the  neck,  as  is  well 
known,  forms  an  extremely  thin  layer,  sharply  bordered  toward 
the  enamel,  and  sometimes  even  overlapping  the  latter.  Bodecker 
speaks  of  directly  calcified  prisms  in  the  neck-cementum,  which, 
in  his  opinion,  may  be  considered  as  osteoblasts,  infiltrated  with 
lime-salts.  Sometimes  the  prismatic  structure  is  not  pronounced, 
but  a  row  of  spindles  is  seen  arranged  in  a  direction  almost 
perpendicular  to  the  surface  of  the  tooth.  Larger  and  smaller 
spindles  alternate,  the  latter  sometimes  being  so  small  as  to  con- 
vey the  impression  of  fibers. 

"  There  is  a  slight  discrepancy  between  the  statements  of 
Bodecker  and  our  own  observations.  We  fully  concur  with  him 
as  to  the  calcified  prisms;  but  the  spindles,  sometimes  very  con- 
spicuous even  to  medium  powers  of  the  microscope,  we  cannot 
consider  as  formations  of  the  basis-substance.  Rather,  we 
should  regard  the  spindles  and  alternating  fibers  as  protoplasmic 
formations,  which  fill  the  interstices  between  the  prismatic  pieces 
of  the  cementum  of  the  neck.  This  tissue,  in  our  opinion,  is 
either  composed  of  prisms  alone,  with  intervening  light  and 
parallel  spaces,  or  of  prisms,  between  which  are  protoplasmic 
bodies  of  spindle  shape,  alternately  broad  and  narrow,  in  the 
latter  instance  having  the  aspect  of  coarse  fibers  of  living  mat- 
ter. Thus  the  uniformity  in  the  structure  of  the  cementum  of 
the  neck  is  established.  We  hope  Dr.  Bodecker,  with  whom 
we  thoroughly  concur  in  all  other  points,  will  pardon  our  heresy 

*  "A  Manual  of  Dental  Anatomy.  "■     Philadelphia,  1876. 


120 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


and  eventually  satisfy  himself  that  our  conception  renders  this 
structure  more  comprehensible  than  does  his.     (See  Fig.  7-.) 

"  Considerable  interest  attaches  to  the  layer  of  dentine 
directly  subjacent  to  the  prismatic  layer  of  the  cementum  of  the 
neck.  AVe  are  indebted  to  John  Tomes  for  the  knowledge  of , 
the  fact  that  the  dentinal  fibers,  in  this  situation,  stop  short  of 
the  cementum.  AVe  may  say  that  nowhere  does  the  structure 
of  the  teeth  vary  in  aspect  so  greatly  as  in  the  dentine  in  the 
region  of  the  neck.  There  are  scarcely  two  teeth  perfectly 
alike  in  this  region.  The  simplest  form  is  when  the  prismatic 
layer  is  directly  followed  by  a  granular  layer  of  dentine,  lacking 

Fig.   72. 


Neck   op  a  Bicuspid  in  Loxgitudixal  Sectiox.      Staixed  with  Chloride  of  Gold. 

/",  pericementum ;  T,  thickness  of  the  specimen:  JV,  cementum  of  the  neck,  composed  of 
prisms  and  intervening  spindles  and  fibers:  Z,  stratified  interzonal  layer:  .D,  coarsely  reticu- 
lated layer  of  dentine,  destitute  of  dentinal  fibers.     Magnified  3200  diameters. 


canaliculi.  That  the  granulation  means  a  rich  reticulum  of 
li^^ng  matter,  coarser  than  in  any  other  part  of  the  dentine, 
and  rendering  the  neck  excessively  sensitive,  John  I.  Hart  has 
proven,  fully  in  accordance  with  Bodecker's  statements.  This 
simple  arrangement,  however,  is  rare.  In  many  instances  there 
are  layers  of  stratifications  between  the  cementum  and  the 
granular  dentine,  greatly  varying  in  breadth  and  in  numbers. 
The  appearance  of  strata,  in  accord  with  the  conception  of  John 
I.  Hart,  means  that  alternate  layers,  rich  in  living  matter,  and 
others  scantily  supplied  with  it,  build  up  the  neck-region  of  the 


THE    MIXUTE    STRUCTURE    OF    CEMENTUM. 


121 


dentine.  Club-like  or  pear-shaped  spaces,  filled  with  proto- 
plasm, are  often  seen  to  pervade  the  granular  layer  of  the  den- 
tine with  a  peculiar  regularity,  and  often  in  connection  with 
dentinal  fibers,  which  otherwise  do  not  reach  the  boundary  of 
the  cementum.  In  Fig.  72  we  find  represented  in  the  granular 
layer  of  the  dentine  coarse,  dark-violet  dots,  forming  points  of 
intersection,  and  far  too  small  to  be  termed  protoplasmic  bodies 
or  cells  in  the  sense  of  older  histologists.     All  these  features 

Fig.   73. 


Neck  of  a  Grouxd  Bicuspid.    Anomalous  Arraxgemen't  of  Layers  of  the  Cementum 

AXD  the  Dentine. 

P,  pericementum  ;  T,  thickness  of  the  specimen  ;  .9,  stratified  layer  of  cementum,  composed 
of  halved  prisms;  L^,  outer  lamellated  layer;  G,  outer  granular  layer;  L-.  inner  lamellated 
layer;  (?-,  inner  granular  layer;  D\  thoroughly  calcified  glossy  layer;  D-,  inner  prismatic 
layer  ;  D,  normal  dentine.    Magnified  200  diameters. 


seem  to  mean  a  markedly  augmented  amount  of  living  matter, 
which  renders  all  surgical  interference  in  the  region  of  the  neck 
so  painful. 

"  The  most  complicated  structure  that  we  have  ever  seen  in 
the  region  of  the  neck  is  illustrated  in  Fig.  73. 

"  The  figure  is  taken  from  a  ground  bicuspid,  which  shows  at 
its  crown  a  distinct  mechanical  abrasion.     The  stratifications 


122  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

extend  all  over  the  root.  It  is  impossible  to  bring  them  into  a 
relation  with  the  mechanical  abrasion,  and  we  should  consider 
this  formation  a  rather  anomalous  one.  The  layers  are  as  fol- 
lows :  The  outermost  portion,  directly  bordering  the  cementum, 
is  composed  of  large,  regular  prisms,  which  show  faint  longi- 
tudinal lines  and  are  halved  by  distinct  fissures  in  a  direction 
parallel  to  the  surface;  this  layer  extends  to  the  close  vicinity  of 
the  enamel,  and  far  down  along  the  root,  directly  changing  into 
stratified  cementum,  devoid  of  cement-corpnscles,  so  far  as  the 
specimen  shows.  This  is  the  only  la^^er  that  belongs  to  the 
cementum,  since  in  the  neighborhood  of  the  enamel  the  dentinal 
fibers  are  traceable  up  to  the  prisms,  pervading  a  granular  basis- 
substance  as  yet  but  slightly  stratified.  Soon  afterward  the 
dentine  begins  to  exhibit  a  number  of  layers,  which  may  be 
defined  as  composing  a  narrow  outer,  and  a  broad  inner,  lamel- 
lated  stratum,  between  which  strata  lies  the  '  outer  granular' 
zone,  somewhat  varying  in  breadth  along  the  root.  These  three 
strata  are  pierced  by  extremely  delicate  radiating  lines,  which 
closely  resemble  dentinal  fibers.  The  next  layer  to  form  is  the 
'inner  granular,'  greatly  changing  in  breadth  in  different  por- 
tions of  the  root.  This  layer  holds  small,  angular  protoplasmic 
formations,  and,  obviously,  corresponds  to  the  granular  layer 
subjacent  to  the  cementum  of  the  neck  in  normal  teeth.  In- 
wardly there  follows  a  zone  (D^)  marked  by  a  high  gloss  due 
to  an  intense  calcification  of  the  basis-substance,  pierced  by 
scanty  angular  protoplasmic  bodies.  The  innermost  stratum 
appears  to  be  composed  of  prisms  or  spindles,  far  less  regular 
than  those  of  the  cementum.  A  sharp  line  of  demarcation,  in 
which  not  the  slightest  anomaly  can  be  made  out,  closes  this 
layer  at  its  approach  to  the  normal  dentine.  All  these  layers 
are  seen  down  to  nearly  half  the  length  of  the  root,  where  the 
specimen  is  cut  off. 

"  Exceptional!}'  there  is  observable  in  the  dentine  of  the  roots 
stratification,  consisting  of  narrow,  light  lines,  arranged  nearly 
parallel  to  the  surface,  causing  an  interruption  in  the  course  of 
the  dentinal  fibers,  but  never  a  change  in  their  direction.  Strati- 
fication of  the  dentine  at  the  neck  is  far  more  common,  but  has 
never  been  seen  as  yet  in  such  perfection  as  in  the  specimen 
illustrated  in  Fig.  73.  What  the  cause  of  such  stratification  is, 
future  studies  in  the  history  of  development  of  the  dentine  of 
the  roots  and  the  cementum  will  elucidate. 


THE    MINUTE    STRUCTURE    OF    CEMEXTUM. 


123 


"  Devitalized  Cementum. — We  have  ground  a  number  of  teeth 
which,  to  judge  from  their  naked-eye  appearance,  were  pulpless 
and  devitalized.  After  the  exposure  of  thin  slabs  obtained 
from  such  teeth  to  the  solution  of  chloride  of  gold,  with  subse- 
quent decalcification  with  acetic  acid,  the  image  under  the 
microscope  was  striking.     (See  Fig.  74.) 

"  The  most  conspicuous  features  were  the  empty  lacuna,  desti- 
tute of  nucleated  protoplasm,  but  containing  granular  clusters 


Cemextum  of  the  Root  of  a  Devitalized  Molar.    Staixed  with  Chloride  of  Gold. 

L,  lacuna,  holding  shriveled  protoplasm  ;   C,  empty  canaliculi ;   B,  basis-substance,  pierced 
by  a  light  reticulum.    Magnified  1200  diameters. 


of  a  dark-violet  color,  obviously  the  shriveled  remains  of  pro- 
toplasm. iSTumerous  canaliculi  arose  from  the  lacunae,  all  of 
which  were  empty.  The  finest  oftshoots  of  both  the  lacunae 
and  canaliculi  produced  alight  net-work  in  the  dark-violet  basis- 
substance, — an  image  which  corresponds  to  dry  and  also  to  ne- 
crotic bone.  Unfortunately,  some  specimens  of  living,  freshly- 
extracted  teeth  furnished,  after  the  same  chemical  treatment, 
identically  similar  figures.     Such  an  untoward  result  has  also 


124  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

occurred  to  other  investigators  who  resorted  to  the  gold  method. 
The  cause  of  such  failure  may  have  been  that  the  extracted 
teeth  were  left  too  long  under  the  influence  of  the  table-salt 
solution  ;  or,  possibly,  the  acetic  acid  worked  in  a  wrong  way. 
All  we  can  say  is,  that  whenever  such  a  negative  result  was 
obtained,  the  whole  cementum  had  been  affected,  so  much  so  that 
we  are  at  a  loss  to  state  whether  or  not  the  devitalized  cementum 
is  dead  all  through,  up  to  the  pericementum.  Future  examina- 
tions, carried  out  with  improved  methods,  vdll  probably  settle 
the  question  where  the  boundary  between  dead  and  living  tissue 
is,  this  being  a  matter  of  the  greatest  importance  to  the  prac- 
titioner." 


CHAPTER    XIII. 

SYNOPSIS  OF  THE  DEVELOPMENT  OF  THE  TEETH. 

From  a  morphological  point  of  view,  we  might,  as  several 
writers  have  done,  consider  the  teeth  to  be  dermal  structures. 
Their  analogy  to  the  skin  is,  indeed,  striking,  if  we  compare  the 
crown  of  a  tooth  with  a  papilla  of  the  skin,  especially  when  the 
former  is  in  a  state  of  formation, — viz,  about  the  fifth  month 
of  intra-uterine  development.  Here  we  observe  a  knob-like  for- 
mation of  connective  tissue,  the  dental  papilla,  similar  to  a  skin- 
papilla,  supplied  with  blood-vessels  and  covered  by  an  epithelial 
tissue,  the  enamel-organ. 

The  teeth,  during  their  early  stage  of  development,  are  com- 
posed of  only  two  tissues, — i.e.,  the  enamel  and  the  dentine,  the 
cementum  of  the  root  being  developed  after  birth. 

The  first  process  in  the  formation  of  teeth  in  the  human  sub- 
ject is  the  evolution  of  a  furrow  extending  the  whole  length  of 
the  future  alveolar  process.  This  furrow  appears  at  about  the 
sixth  week  of  intra-uterine  life.  (See  Fig.  75.)  Shortly  afterward 
we  observe  along  the  furrow  a  row  of  hillocks  in  the  oral  epi- 
thelium, growing  down  into  the  substance  of  the  future  jaw. 
This  hillocked  epithelial  formation  is  called  an  enamel-cord,  and 
as  development  proceeds,  the  enamel-cord  is  formed  which 
becomes  the  enamel-organ  of  each  tooth.  About  the  third 
month  this  epithelial  cord  widens  at  its  distal  extremity,  which 
assumes  the  shape  of  a  bell-jar  at  the  end  of  the  cord.     The  for- 


SYNOPSIS  OF  THE  DEVELOPMENT  OF  THE  TEETH. 
Fig.  75. 


125 


Transverse  Section  of  Furrow  on  Lower  Jaw  op  a  Human  Ejibkto  Six  "Weeks  Old. 
E,  epithelium  of  oral  mucosa;  T,  tongue:   V,  blood-vessels;  B,  base  of  oral  cavity:  F,  fur- 


row in  transverse  section. 


Magnified  75  diameters. 
Fig.  76. 


Epithelial   Cord  tei;minaii.\i. 


THE  Future  ExAiiEL-OKLrAX  of  a  Human  Embryo 
Three  Months  Old. 
0,  stratified  epithelium  of  the  oral  cavitj- ;  Co,  epithelial  cord  of  the  enamel-organ  ;  .S",  short 
secondary  offshoot  of  the  epithelial  cord ;  SP,  broad  secondary  offshoot  of  the  epithelial  cord  ; 
EE,  external  or  outer  epithelium  ;  £■  (lower),  internal  or  inner  epithelium;  J/,  medullary  tissue 
sprung  from  previous  epithelia,  the  future  stellate  reticulum  :  /'.dentine-papilla;  Ca,  capsule 
or  tooth-sac;  £"  (upper),  embryonal  tissue,  the  future  fibrous  connective  tissue  of  the  mucous 
membrane.    Magnified  75  diameters. 


126  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

mation  tlirougliout  is  composed  of  two  distinct  layers  of  colum- 
nar epithelia,  continuous  with  the  oral  mucous  membrane.  (See 
Fig.  76.)  At  the  period  in  which  the  bell-shape  begins,  we  see 
the  first  trace  of  the  dentinal  papilla.  About  the  end  of  the 
third  month  of  intra-uterine  development  we  observe  that  the 
enamel-organ  has  changed  considerably  in  shape  and  size,  and 
we  now  distinguish  the  following  formations:  1,  the  epithelial 
cord;  2,  the  external  epithelium;  3,  the  internal  epithelium;  4,  the 
stratum  intermedium  ;  and  5,  the  stellate  reticulum.  (See  Fig.  77.) 
We  also  notice  the  beginning  formation  of  the  tooth-sac,  which 
grows  upward  from  the  dentine  papilla,  gradually  encircling  the 
enamel-organ.  About  the  fifth  month  the  external  epithelium 
of  the  enamel-organ,  together  with  the  epithelial  cord,  begin 
to  break  into  epithelial  nests  and  buds,  amid  which  a  pro- 
fuse formation  of  red  blood-corpuscles  and  blood-vessels  takes 
place.  At  this  period  the  internal  epithelium  covering  the 
crown  of  the  future  tooth  undergoes  a  change  consisting  in  a 
prolongation  of  the  single  epithelia,  and  their  sum-total  is  now 
called  the  amdohlast  h'lU'r.,  while  those  elongated  formations 
covering  the  dentine  papilla  are  termed  odontoblosf.'--.  The  amelo- 
blasts  and  odontoblasts  have  been  originally  in  close  contact, 
but  with  progressing  development  the  dentine  begins  to  form 
from  the  periphery  toward  the  center  of  the  tooth  ;  the  enamel, 
on  the  contrary,  grows  from  the  surface  of  the  dentine  outward. 
These  changes  appear  in  about  the  fifth  month,  wherein  also  the 
first  trace  of  dentine  is  seen,  while  the  enamel  begins  to  form  at 
about  the  sixth  month.  Before  calcification  takes  place,  there 
becomes  visible  on  the  outermost  portion  of  the  ameloblasts  a 
delicate  light  zone,  consisting  of  embryonal  or  medullary  cor- 
puscles, from  which  the  enamel  originates.  The  odontoblasts 
at  the  periphery  of  the  dentine  papilla  likewise  undergo  a 
transformation  into  medullary  corpuscles,  and  by  their  calcifica- 
tion give  rise  to  the  basis-substance  of  the  dentine.  The  odonto- 
blasts, as  well  as  the  medullary  corpuscles  sprung  from  them, 
are  interconnected  by  delicate  threads  of  living  matter.  These 
threads,  in  coalescence  with  the  ofishoots  of  the  odontoblasts, 
produce  the  dentinal  fibers.  The  odontoblasts  and  ameloblasts, 
therefore,  are  not  directly  transformed  into  the  tissues,  dentine 
and  enamel,  which  they  respectively  represent,  but  must  be  con- 
sidered as  provisional  formations.  During  development,  the  den- 
tine is  formed  of  globular  territories,  proven  by  the  occurrence 


.SYNOPSIS    OF    THE    DEVELOPMENT    OF    THE    TEETH. 


127 


of  interglobular  spaces,  and  by  the  retrogressive  processes  of 
absorption  in  temporary  teeth,  in  caries  and  ebiirnitis.  In  this 
process,  the  similarity  of  dentine-tissue  with  bone-tissue  is  ren- 
dered evident. 

The  cementum  is  formed   after  birth ;   the   remains   of  the 

Fig.  77. 


'i^^'"?^      NX^  ;:>-^ 


Epithelial  Coed  teemisatixg  is  the  Examel-Orgax  of  a  Hcman  Embryo  Five  Months 

Old. 

0,  stratified  epithelium  of  the  oral  cavity :  SP,  secondary  offshoot  of  the  epithelial  cord  : 
Co.  epithelial  cord  of  the  enamel-organ;  J/,  myxomatous  tissue  of  the  enamel-organ:  EE, 
external  or  outer  epithelium;  IE,  internal  or  inner  epithelium;  /,  stratum  intermedium, 
between  inner  epithelium  and  myxomatous  tissue;  /-'.papilla;  Ca,  capsule  or  tooth-sac;  F. 
fibrous  connective  tissue  of  oral  mucosa.    Magnified  75  diameters. 


128  THE    ANATOMT    AND    PATHOLOGY    OF    THE    TEETH. 

tooth-sac  changing  into  meclnhary  corpuscles,  from  which  the 
cementuni  is  developed  in  the  same  manner  as  bone-tissue. 

The  twenty  anterior  permanent  teeth  are  developed  from 
enamel-organs,  being  oifshoots  from  those  of  the  temporary 
teeth.  All  the  permanent  molar  teeth  are  an  offspring  of  the 
enamel-organ  of  the  second  temporary  molar  teeth. 

The  Avriter's  views  concerning  the  development  of  the  teeth,  as 
here  propounded,  differ  considerably  from  those  entertained  by 
previous  authors.  To  enable  future  investigators  to  satisfy 
themselves  of  the  correctness  of  his  assertions,  the  result  of 
eight  years  of  labor,  the  following  is  presented  as  the  method 
resorted  to  in  the  pursuit  of  this  study,  one  of  the  most 
fascinating  subjects  of  microscopical  research : 

To  prepare  microscopical  specimens  of  embryonal  jaws  for 
researches  in  the  history  of  the  development  of  the  teeth,  the 
jaw-bones  (preferably  the  lower)  are  excised  from  the  foetus, — 
care  being  exercised  not  to  squeeze  the  specimen, — and  are 
placed  in  a  one-iifth  of  one  per  cent,  solution  of  chromic  acid. 
The  liquid  must  be  changed  every  third  or  fourth  day,  and  the 
strength  of  the  chromic-acid  solution  gradually  increased  to  one- 
half  of  one  per  cent.,  until  the  hard  tissues,  by  the  removal  of 
the  lime-salts,  are  sufficiently  soft  to  be  cut  with  a  razor.  All 
trials  to  determine  the  degree  of  softness  of  such  a  specimen 
must  be  made  by  means  of  a  needle,  and  not  with  the  fingers. 
The  epithelial  structures  are  especially  liable  to  be  crushed, 
unless  handled  with  the  utmost  care.  The  greatest  obstacle  to 
obtaining  perfect  specimens  is  caused  by  the  fact  that  the  enamel- 
organ  is  withdrawn  from  the  dentinal  cap,  and  the  epithelia 
are  detached  from  the  connective-tissue  structures,  a  cavity 
beino-  thus  formed  whose  walls  offer  no  resistance  to  the  cuttino-- 
instruments,  and  are  thus  easily  detached  from  their  normal 
position. 

After  having  tried  different  methods  of  imbedding,  the  author 
has  come  to  the  conclusion  that  the  best  material  for  this  purpose 
is  celloidin,  softened  in  absolute  alcohol  and  dissolved  in  sulphuric 
ether.  The  specimen,  previous  to  imbedding,  must  be  dehy- 
drated by  immersion  in  absolute  alcohol  for  twenty-four  hours. 
It  is  next  kept  in  a  mixture  of  equal  parts  of  sulphuric  ether 
and  absolute  alcohol  about  twenty-four  hours  longer.  Then  it 
is  held  in  a  rather  thin  solution  of  celloidin  for  about  two 
days,  after  which  it  is  ready  for  mounting  upon  a  cork.     When 


DEVEL0P3IEXT    OF    DEXTIXE.  129 

such  a  specimen  is  cut,  it  will  usually  be  found  that  the  spaces 
between  the  dentine  and  enamel,  which  are  due  to  the  shrinkage 
of  the  myxomatous  tissue  of  the  enamel-organ,  are  filled  with 
celloidiu.  If,  however,  it  is  found,  upon  cutting,  that  such  a 
space  has  not  been  completely  filled,  a  very  thin  solution  of  cel- 
loidin  may  be  poured  into  it.  A  section-cutter  is  of  great 
advantage,  since  bv  its  use  a  laro^e  number  of  thin  and  uniform 
specimens  can  be  obtained  in  a  comparatively  short  space  of  time. 
Chemically-pure  glycerin  is  considered  far  superior  to  Canada 
balsam  as  a  mounting  medium,  the  tissues  of  the  object  pre- 
senting in  this  medium  a  more  distinct  appearance.  If  high 
powers  of  the  microscope  are  to  be  employed,  only  glycerin- 
mounted  specimens  will  give  satisfactory  results. 


CHAPTER  XIV. 

DEVELOPMEXT   OF  DEXTIXE.* 

Dentine,  as  is  universally  admitted,  is  strictly  an  offspring 
of  connective  tissue  produced  by  the  papilla,  a  formation  of 
embryonal  tissue,  crowded  with  medullary  corpuscles.  (See 
Fig.  78.) 

It  appears  about  the  end  of  the  second  and  the  beginning  of 
the  third  month  of  intra-uterine  life,  at  a  time  when  the  extrem- 
ity of  the  epithelial  cord  has  flattened  and  assumed  a  cup-shape. 
The  cavity  of  this  cup  is  filled  with  the  papilla,  which  sends 
prolongations  along  the  outer  wall  of  the  cup,  the  future  sac  of 
the  tooth.  The  more  this  is  deepened  and  widened,  the  larger 
will  be  the  papilla.,  If  the  cup  of  the  enamel-organ  shows  de- 
pressions corresponding  to  a  bicuspid  or  molar  tooth,  we  shall 
find  corresponding  elevations  upon  the  papilla  extending  into 
them. 

The  papilla  is  originally  supplied  with  but  few  capillary 
blood-vessels.  With  advancing  growth,  however,  the  vascular 
supply  becomes  greater,  especially  in  its  peripheral  portions, 
where  a  delicate  fibrous  connective  tissue  is  developed, — the  so- 
called  tooth-sac.     In  the  seventh  month  of  fcetal  life,  we  observe 

*  •  ■  Contributions  to  the  History  of  Development  of  the  Teeth.  ■ "  By  C.  Heitzmann 
and  C.  F.  W.  Bodecker.      Tlie  Indejyendent  Practitionei^  vols,  viii  and  ix. 

10 


130 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


a  perfect  vascular  apparatus  traversing  the  papilla,  consisting  of 
arteries,  veins,  and  capillaries.  If  examined  with  low  powers  of 
the  microscope,  the  papilla  appears  to  be  composed  of  small, 
globular,  highlj-refracting  corpuscles,  amid  which  is  seen  a 
scanty  basis-substance.  With  high  powers  of  the  microscope, 
we  observe  globular  or  oblong  corpuscles  of  small  size,  which 
are  either  compact  and  homogeneous,  or  possessed  of  a  distinct 
reticular  structure  in  their  interior.  Between  small  groups  of 
such  medullary  corpuscles,  spindle-shaped  tracts  appear,  corre- 
sponding to  the  boundaries  of  the  future  territories  of  the  myxo- 
matous tissue,  the  reticulum  of  which  in  the  human  subject  is 
always  incomplete,  never  attaining  the  degree  of  development 

Fig.  78. 


Medullary  Tissue  of  the  Papilla  of  a  Human  Embryo  of  Four  Months. 

The  small  shining  medullary  corpuscles  form  clusters,  around  which  we  observe  an  irregularly 
developed  ms'xomatous  net-work.    Magnified  1200  diameters. 


seen  in  the  enamel-organ.  The  largest  medullary  corpuscles  are 
observed  in  the  middle  of  territories  surrounded  b}^  a  certain 
amount  of  basis-substance.  Both  these  corpuscles  and  the  basis- 
substance  have  a  distinct  reticular  structure.     (See  Fig.  78.) 

The  more  the  papilla  increases  in  size  and  advances  in  devel- 
opment, the  less  frecjuent  are  the  homogeneous  and  small 
medullary  corpuscles,  while  the  granular  corpuscles  are  larger, 
each  being  surrounded  by  a  small  amount  of  basis-substance. 
Along  the  periphery  of  the  papilla,  however,  there  is  invariably 
present  a  narrow  zone,  in  which  the  medullary  corpuscles  are 
more  numerous  and  more  shining  than  in  the  rest  of  the  papilla. 


itEVELOPMENT    OE    DENTi:SE.  131 

In  the  fifth  month  the  outermost  periphery  of  the  papilla  is  fre- 
quently found  to  be  composed  of  a  hyaline  rim,  beneath  which 
is  a  narrow  zone  of  medullary  corpuscles.  The  hyaline  rim 
corresponds  to  the  so-called  structureless  layer,  or  basement 
membrane  so  often  seen  between  epithelial  and  connective-tissue 
formations.  When  the  enamel-organ  is  detached  from  the 
papilla, — and  this  detachment  is,  as  above  said,  very  frequent, — 
the  outer  surface  of  the  basement  membrane  appears  beset  with 
an  extremely  delicate  fringe,  evidently  the  torn  connection  be- 
tween the  papilla  and  the  adjacent  enamel-organ,  or  the  amelo- 
blasts.  High  powers  of  the  microscope  reveal  in  the  apparently 
structureless  layer  a  faint  reticular  formation,  and  marks  of  a 
division  into  medullary  corpuscles. 

At  the  iDCginning  of  the  fifth  month,  we  usually  find  along  the 
periphery  of  the  papilla  the  first  traces  of  peculiar,  elongated 
corpuscles,  known  as  odontoblasts.  These  formations  are  ob- 
long, pear-,  club-,  or  spindle-shaped,  arising  from  the  coalescence 
of  a  number  of  medullary  corpuscles,  including  that  portion 
which  has  been  previousl}^  transformed  into  basis-substance. 
The  odontoblasts  are  sometimes  seen  directly  beneath  an  already- 
formed  layer  of  not  yet  calcified  dentine.  The  latter,  in  this 
case,  is  sufiiciently  characterized  by  the  presence  of  delicate 
branching  dentinal  canaliculi,  holding  the  slender  dentinal 
(Tomes)  fibers.  AYe  often  observe  these  fibers  to  be  in  direct 
connection  with  adjacent  odontoblasts.  If  an  odontoblast  ter- 
minates in  a  sharp  point,  one  ofi'shoot  directly  connected  with 
a  dentinal  fiber  is  seen  to  arise  from  the  point.  If  an  odonto- 
blast has  a  broad  basis,  two  or  more  offshoots  may  arise  from 
it  and  run,  in  the  shape  of  dentinal  fibers,  into  the  adjacent 
dentinal  canaliculi.  It  may  also  happen  that  an  offshoot  of  an 
odontoblast  takes  another  direction,  and  instead  of  passing  into 
a  dentinal  canalicukis,  runs  parallel  with  the  border  of  the 
already-formed  dentine.  Fully-developed  odontoblasts  are  not 
often  seen  in  direct  union  with  dentine,  and  this  is  especially 
true  along  the  lateral  portions  of  the  dentinal  cap.  It  is  far 
more  common  that  medullary  corpuscles  are  present  between 
the  odontoblasts  and  the  dentine,  and  that  the  offshoots  of  the 
odontoblasts  run  between  these  medullary  corpuscles  in  order 
to  reach  their  respective  dentinal  canaliculi.  Fully-developed 
odontoblasts  are  rarely  seen  at  the  apex  of  the  papilla.  Usually 
medullary  corpuscles   only  are  present  in  this  locality,  or  they 


132 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


are  interposed  bet^'eeii  the  odontoblasts  and  dentine.  Not  in- 
frequently we  observe  in  the  forming  dentine  layers  as  are 
represented  in  Fig.  79. 

The  odontoblasts  have  arisen  from  the  fusion  of  a  number  of 


First-Formed  Dentine  of  a  Human  Fcktus  of  Six  Months. 

D,  calcified  layer  of  dentine  with  marked  globular  territories  ;  DT,  dentine  composed  of  a 
non-calcified  basis-substance,  likewise  globular ;  DM,  row  of  medullary  corpuscles  before  the 
formation  of  basis-substance  ;  0,  odontoblasts,  the  ofi'shoots  of  which  run  between  the  medul- 
lary corpuscles  into  the  dentinal  canaliculi ;  E,  enamel.    Magnified  1200  diameters. 

medullary  corpuscles,  and  are  present  where,  at  the  time,  the  for- 
mation of  dentine  is  not  actively  in  progress.  "Whenever  this 
is  the  case,  the  odontoblasts  break  up  into  medullary  corpuscles. 


DEVELOPMENT  OF  DEXTIXE,  133 

which  are  directly  transformed  into  the  basis-substance  of  the 
dentine.  The  oiFshoots  of  the  odontoblasts,  that  are  seen  to 
run  directly  into  the  dentinal  canaliculi,  appear  between  the 
medullary  corpuscles  as  soon  as  the  odontoblasts  split  up  into 
such  corpuscles.  The  offshoots  are  formations  of  living  matter 
seen  to  emanate  from  a  compact  layer  at  the  base  and  the 
borders  of  the  odontoblasts.  The  dentinal  fibers  remain  in 
situation  after  the  formation  of  medullary  corpuscles,  or  they  are 
newly  formed  between  the  medullary  corpuscles,  as  soon  as  the 
dentinal  canaliculi  are  formed.  The  odontoblasts  are  not  direct 
dentine-formers,  but  provisional  formations,  from  which  arise 
the  medullary  corpuscles,  and  these  are  changed  into  the  basis- 
substance  of  the  dentine.  Odontoblasts,  therefore,  the  same  as 
ameloblasts,  are  provisional  formations,  and  dentine,  as  well  as 
enamel,  originates  from  medullary  corpuscles  in  the  same  manner 
in  which  all  forms  of  connective  tissue  are  known  to  arise. 

It  is  the  rule  that  the  medullary  corpuscles  are  at  first  trans- 
formed into  a  basis-substance,  which  is  as  yet  destitute  of  lime- 
salts.  In  specimens  stained  with  carmin,  this  zone  of  non- 
calcified  dentine  assumes  a  bright  red  color,  in  contradistinction 
to  the  calcified  portion,  which  either  remains  unstained  or 
assumes  a  greenish  tint  by  the  reduction  of  the  chromic  acid. 
Another  distinction  between  the  non-calcified  and  the  calcified 
basis-substance  is  that  the  latter  has  a  markedly  higher  degree 
of  refraction  than  the  former.  When  we  examine  such  a  speci- 
men with  high  powers  of  the  microscope,  we  at  once  become 
convinced  of  the  identity  of  the  structure  of  both  the  non-calci- 
fied and  the  calcified  dentine.  We  observe  a  markedly  reticular 
structure  in  both,  and  in  many  instances  fine  filaments,  emanat- 
ing from  the  dentinal  fibers,  are  seen  to  penetrate  the  reticulum. 

At  the  periphery  of  ttie  dentine,  the  bifurcations  of  the 
dentinal  canaliculi  and  their  tenants  are  always  plainly  marked. 
This  feature  obviously  arises  from  an  aggregration  of  smaller 
medullary  corpuscles  than  those  appearing  at  a  later  period  of 
development.  At  the  same  time,  the  reticulum  in  the  basis- 
substance  is  more  delicate  in  the  region  of  the  bifurcations,  and 
consequently  the  meshes  of  the  basis-substance  appear  narrower 
in  the  first-formed  dentine  than  in  that  which  is  formed  at  a 
later  period.  We  sometimes  observe,  in  connection  with  longi- 
tudinal sections  of  dentine,  transverse  sections  which  are  of 
great  interest.     (See  Fig.  80,  BC.)     Here  it  is  seen  that  the 


134 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


calcification  first  starts  at  the  periphery  of  the  fields  farthest 
from  the  dentinal  canaliculi.  Thus  a  comparatively  coarse  net- 
work of  calcified  basis-substance  is  established,  in  the  meshes 
of  which  we  observe  either  an  uncalcified  basis-substance  or 
unchanged  protoplasm,  whereas  the    central  portions  of  the 

Tig.  80. 


First-Formed  Dentine  of  the  Molar  Tooth  op  a  Human  Fcetus  op  Six  Months. 

DB,  basis-substance  of  non-calcified  dentine  ;  BL,  basis-substance  of  calcified  dentine,  both 
in  longitudinal  section  :  I)C,  calcified  dentine  in  crois-section.    Magnified  1200  diameters. 

meshes  are  occupied  1)y  the  dentinal  fibers  in  transverse  or 
oblique  section.  The  latter  appear  larger  in  inverse  ratio 
to  the  amount  of  calcareous  matter  that  has  been  deposited. 
From  their  periphery  arise  the  spokes,  also  seen  in  fully-devel- 


DEVELOPMENT  OF  DEXTIXE.  135 

oped  dentine,  wliieh  traverse  a  light  rim — the  future  canali- 
culus. The  horder  of  the  canaliculus  is  often  marked  hy  a 
circular  or  crescentic  formation,  possildy  the  future  rim  of 
elastic  substance  of  the  dentinal  canaliculi. 

The  line  of  the  non-calcified  basis-substance  forming  the 
l)onndary  toward  the  medullary  corpuscles  is  found  to  be  either 
straight,  stair-like,  or  slightly  wavy.  This  feature  is  never 
observed  close  to  the  periphery  of  the  dentine,  Ijut  always 
some  distance  awaj'  from  it.  These  wavy  contours  unquestion- 
ably correspond  to  the  globular  territories  of  which  the  basis- 
substance  is  composed.  Previous  researches  regarding  dissolu- 
tion of  the  dentine  of  temporary  teeth,  in  caries  and  in  the 
process  of  e1)urnitis,  especially  in  the  latter,  have  strongly 
pointed  toward  the  presence  of  globular  territories  in  the 
dentine,  the  same  as  in  l)one-tissue.  The  history  of  develop- 
ment corroborates  the  presence  of  such  territories,  since  they 
are  of  very  common  occurrence  in  developing  dentine  of  man, 
as  well  as  of  diiferent  animals.  Their  origin-  is  explained  in  a 
grouping  together  of  a  certain  number  of  medullary  corpuscles 
previous  to  their  transformation  into  basis-substance.  Each 
glol:)ular  territory  is  pierced  by  a  number  of  dentinal  canaliculi, 
without  the  least  interruption  in  their  course.  We  desire  to 
lay  special  stress  .upon  the  fact  that  such  territories  become 
conspicuous  only  after  calcification  of  the  basis-substance 
has  taken  place.  Under  the  theory  that  tlie  odontoblasts  are 
directly  transformed  into  dentine,  the  formation  of  globular 
territories  was  inexplicable.  In  morbid  processes,  we  observe 
the  globular  territories  of  the  dentine  breaking  up  into  a  num- 
ber of  medullary  corpuscles.  The  history  of  development 
teaches  us  that  each  territory  arises  from  a  number  of  smaller 
corpuscles.  Thus  the  formation,  .  dissolution,  inflammation, 
and  reformation  of  dentine  become  plain. 

Since  Czermak  has  drawn  attention  to  uncalcified  fields  in 
the  dentine  of  many  teeth,  and  called  them  "  interglobular 
spaces,"  a  great  deal  of  speculation  has  been  indulged  in  to 
explain  this  occurrence.  Such  spaces  are  never  present,  as  far 
as  the  writers  have  observed,  close  to  the  periphery  of  the  den- 
tine, l:)ut  are  always  found  some  distance  from  the  lufurcations 
of  the  dentinal  canaliculi,  and  sometimes  are  scattered  through- 
out the  dentine.  These  spaces  are  filled  with  a  non-calcified 
basis-substance,  or  with  medullary  corpuscles  that   have  not 


136 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


been  trant>formed  into  basis-substanee.  We  have  often  observed 
within  these  spaces  irregular  globular  territories,  invariably 
marked  bv  the  contours  of  such  territories,  but  never  causing  a 
deviation  of  the  course  of  the  dentinal  canaliculi. 


Fig.  81. 


GD 


CD 


Anomalous  Foematiox  of  Dentine  fbom  a  Human  FffiTus  of  Six  Months. 

r,  papilla  of  the  tooth,  with  a  few  blood-vessels,  and  no  odontoblasts.  The  medullary  cor- 
puscles, close  below  the  dentine,  are  arranged  in  groups,  corresponding  to  the  future  territories 
of  the  dentine;  CI),  non-calcified  basis-substance  of  the  dentine;  D,  calcified  dentine  ;  S,  1,  2, 
and  3,  stratifications  of  the  dentine ;  GD,  ill-calcified  basis-substance  of  the  dentine,  in  con- 
nection with  S'2,  composed  of  globular  territories.    Magnified  oUO  diameters. 


The  origin  of  such  interglobular  spaces  is  traceable  to  the 
earliest  stages  of  the  formation  of  the  dentine.  (See  Fig.  81.) 
In  exceptional  cases  even  fully-developed  dentine  will  appear 
composed  of  layers,  or  with  faint  concentrically-arranged  marks, 


DEVELOPMENT    OF    DENTIXE. 


137 


traversed  without  interruption  bv  the  dentinal  eanalieuli.  Both 
the  stratification  and  the  interglol)uhir  spaces  are  caused  by  a 
taulty  deposition  of  lime-salts  in  the  embrvonal  development  of 
the  dentine.  Their  cause  is  probably  a  temporary  interruption 
of  deposition  of  lime-salts,  owing  to  transient  ailments  of  the 
mother.  These  rather  anomalous  formations  of  dentine  again 
prove  that  the  basis-substance  is  made  up  of  globular  territories, 
and  these,  again,  of  medullary  corpuscles. 

In  the  foetus  of  the  cat,  the  sheep,  and  the  dog,  the  process 

Fig.  82. 


Papilla  axd  Adjacext  Dextixe  op  Foetus  of  a  Pig. 

P,  myxomatous  tissue  of  the  papilla,  with  irregularly  branching  corpuscles,  and  an  abun- 
dance of  myxomatous  basis-substance  ;  C,  €,  capillaries,  partly  fully  formed,  and  partly  in  the 
process  of  formation  ;  0,  layer  of  odontoblasts  :  J),  dentine.    Magnified  500  diameters. 


of  the  formation  of  dentine  is  the  same  as  in  man,  in  all  essen- 
tial features.  The  same  rule  holds  good  for  the  history  of  the 
development  of  dentine  in  swine.  This  dentine,  in  develop- 
ment, differs  slightly  from  that  of  man,  mainly  in  the  structure 
of  the  papilla.     (Fig.  82.) 

The  papilla  of  the  foetus  of  a  pig  is  composed  of  irregular, 
branching,  and  partly  connecting  protoplasmic  bodies,  some- 
what resembling  the   stellate  reticulum  of  the   enamel-oro-an. 


138 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


These  corpuscles  are  nniforml}'  distributed  in  an  abundant  mass 
of  basis-substance,  which,  with  lower  powers  of  the  micro- 
scope, appears  finely  granular.  High  powers,  however,  reveal 
the  delicate  net-work  essential  to  all  the  varieties  of  a  myxo- 
matous basis-substance.  This  tissue  is  traversed  by  a  moderate 
number  of  blood-vessels,  mainly  capillaries,  which  show  in  some 
places  characteristics  of  the  stages  of  development  from  the 
original  solid  cords  of  protoplasm  to  the  vacuolization  and  ap- 
pearance of  endothelia  upon  their  walls.  Toward  the  periphery 
of  the  papilla,  spindle-shaped  bodies  make  their  appearance. 


Fig. 


Fig.  84. 


Odoxtoblasts,  wns  Adjacext  Dextine,  from  the  Fcetus  op  a  Pig. 
0,  odontoblasts ;  D,  dentine.    Magnified  1200  diameters. 

evidently  arising  (at  least  to  a  great  extent)  from  the  living 
matter  previously  hidden  in  the  myxomatous  basis-substance. 
By  an  increase  in  the  size  of  one,  or  the  confluence  of  several, 
such  spindle-shaped  corpuscles,  the  odontoblasts  arise,  and  they 
are  often  seen  in  contact  with  the  already-formed  dentine. 
Close  study  of  specimens  has  satisfied  us  that  the  odontoblasts 
do  not  directly  form  the  basis-substance  of  the  dentine,  but 
here,  as  well  as  in  men  and  other  animals,  are  merely  transi- 
tional formations. 


DEVELOPMEXT  OF  DEXTINE.  139 

111  the  condition  of  rest  the  odontoblasts  oft'er  an  excellent 
opportnnit}'  to  study  their  relation  to  the  dentine.  If  they  lie 
against  the  dentine  with  a  broad  basis,  four  or  five  offshoots 
(as  represented  in  Fig.  83)  may  be  seen  to  enter  the  adjacent 
canaliculi,  all  of  which  arise  from  one  odontoblast.  If,  on  the 
contraiy,  the  odontoblasts  terminate,  toward  the  dentine,  in  a 
point,  a  single  dentinal  fiber  will  spring  therefrom,  as  repre- 
sented in  Fig.  84.  It  may  also  happen  that  a  single  odontoblast 
exhibits  no  offshoots,  in  which  instance  we  observe,  between 
the  base  of  the  odontoldast  and  the  dentine,  delicate  filaments 
which  run  along  the  border  of  the  dentine,  and  from  ^^dlich  arise 
the  dentinal  fibers.  The  opposite  ends  of  the  odontoblasts  are, 
roughly  speaking,  pointed,  and  likewise  elongated  into  delicate 
fibers.  These  fibers,  as  well  as  the  lateral  portions  of  the  odonto- 
blasts, are  interconnected  with  all  their  neighbors  by  means  ot 
delicate  thorn}'  offshoots. 

The  results  of  further  researches  in  this  field ,  as  follows,  have 
been  published  by  Frank  Abbott :  * 

"  The  only  formations  deserving  of  the  term  '  cells'  are  the 
•odontoblasts,  those  peculiar,  elongated  bodies  (of  a  shape  and 
size  to  remind  one  of  columnar  epithelia)  usually  seen  at  the 
periphery  of  the  papilla  in  developing,  and  at  the  periphery  of 
the  pulp-tissue  in  developed  teeth. 

"  We  know  of  these  peculiar  protoplasmic  bodies  that  they  send 
offshoots  (the  dentinal  fibers)  upward  into  the  dentine,  off'shoots 
laterally  connecting  one  with  another,  and  other  off'shoots  down- 
ward, uniting  them  with  the  medullary  elements  of  the  papilla. 

"  The  first  to  see  and  describe  all  these  offshoots  was  Franz 
Boll,  in  1868,  and  he  was  corroborated  by  Waldeyer,  in  1869. 
Before  these  offshoots  were  known,  attempts  at  explaining  the 
formation  of  dentine  were  made,  first  by  A.  Kolliker,  in  1852, 
in  his  hand-book  of  histology.  On  page  385  he  says,  '  In  the 
formation  of  dentine  not  the  whole  pulp  is  concerned,  but  only 
its  outermost  layer  of  epithelium-like  cells,  which,  by  a  contin- 
ual prolongation  of  the  original  cells,  under  a  continuous  midtipli- 
cation  of  the  nuclei,  apparently  keep  up  the  same  thickness. 

"  '  I  am  not  willing  to  maintain  that  one  and  the  same  cell  is 
suflB.cient  for  the  whole  duration  of  the  formation  of  dentine, 
for  I  consider  it  as  quite  possible  that,  from  time  to  time,  the 

*  "  Odontoblasts  in  their  Relation  to  Developing  Dentine.''     Deidal  Cosmos, 


140  TJ[E    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

dentine-cells  are  replaced  by  others  forming  at  their  inner  side. 
What  I  deny  is,  that  the  whole  pulp  is  transformed  and  ossified 
from  without  inward.' 

"  Kolliker,  at  that  time,  knew  nothing  about  the  presence  of 
dentinal  fibers.  To  explain  the  formation  of  the  dentinal  canali- 
culi,  he,  on  page  386,  discusses  the  following  three  possibilities  : 

"  1.  The  canaliculi  are  the  remnants  of  the  cavities  of  the  den- 
tinal cells,  which,  in  the  process  of  ossification,  become  thickened 
and  hardened  in  their  walls,  but  are  not  perfectl}'  closed. 

"  2.  The  canaliculi  originate  from  the  nuclei  of  the  dentinal 
cells,  which  elongate  and  coalesce,  but  retain  their  central  cavities. 

"  3.  The  canaliculi  are  produced  by  a  process  of  resorption  in 
the  previously  homogeneous  dentinal  tissue,  in  a  manner  analo- 
gous to  the  formation  of  the  Haversian  canals,  or  the  canaliculi 
in  the  cementum. 

"  Of  these  three  possibilities,  Kolliker  considered  the  first  as 
the  most  probable  for  the  formation  of  the  main  canaliculi,  and 
was  convinced  that  the  third  possibility  alone  can  explain  the 
origin  of  the  fine-branching  canaliculi.  He  distinctly  states 
that  no  other  tissue  is  concerned  in  the  production  of  dentine  but 
the  cells  which  later  were  dubbed  odontoblasts,  and  that  these, 
by  a  successive  taking  up  of  the  lime-salts,  become  dentine. 
He  therefore,  as  early  as  1852,  although  upholding  until  then  the 
secretion  theory,  adopted,  and  from  that  time  up  to  date  has 
unswervingly  maintained,  as  regards  the  formation  of  dentine, 
the  opposite  or  transformation  theory.  About  ten  years  later,  he 
and  John  Tomes  discovered  the  dentinal  fibers,  and,  with  the 
acknowledged  evidence  of  these  fibers  within  the  canaliculi,  and 
their  connection  with  the  odontoblasts,  the  difiiculties  in  ex- 
plaining the  formation  of  dentine  have  considerably  increased. 

''  Are  the  dentinal  fibers  remnants  of  the  central  portion  of  the 
odontoblasts,  whose  lateral  portions  become  transformed  into 
basis-substance  ?  Are  the  dentinal  fibers  formed  between  the 
odontoblasts  after  the  latter  have  become  basis-substance  ?  So 
great,  indeed,  seemed  the  puzzle,  that  quite  recently  R.  R.  An- 
drews deemed  it  advisable  to  reiterate  a  previously-expressed 
opinion  of  E.  Klein  and  others,  that  there  are  two  sets  of  odon- 
toblasts, some  with  broad  bases  which  become  basis-substance 
altogether,  and  others  pear-  or  spindle-shaped,  with  long  pro- 
jections, which  become  the  dentinal  fibers.  These  latter  they 
termed  '  fibril-cells.' 


DEVELOPMENT  OF  DENTINE.  141 

"  It  would  seem  to  require  a  very  limited  amount  of  histo- 
logical or  microscopical  experience  to  satisfy  oneself  of  the  uu- 
tenableness  of  these  views,  as,  with  not  a  very  high  power, 
projections  may  be  seen  running  from  every  odontoblast  into 
the  canaliculi  of  the  formed  dentine,  some  giving  off  one,  some 
two,  some  three  such  projections;  while  even  as  many  as  five 
offshoots  have  been  seen  arising  from  a  very  broad  end  of  an 
odontoblast,  and  penetrating  the  canaliculi.  The  '  fibril-cells,' 
therefore,  are  nothing  but  narrow  wedges  between  broad-based 
odontoblasts,  especially  numerous  where  the  periphery  of  the 
papilla  forms  a  sharp  curvature,  as  on  the  pointed  cusps. 

"  Several  questions,  however,  require  our  close  attention  in  the 
history  of  the  development  of  dentine.  One  of  these  is,  Are 
the  odontoblasts  absolutely  necessary  as  a  stage  preliminary  to 
the  formation  of  dentine  ?  And  secondly,  how  is  it  that  the 
odontoblasts  produce  a  continuous  mass  of  dentine  from  the 
periphery  to  the  pulp,  if  they  are  converted  into  basis-substance 
in  layers  ?  For  we  know  that  the  dentine  is  only  in  exceptional 
cases  stratified,  whereas  one  would  expect  such  lines  of  stratifi- 
cation to  be  of  common  occurrence,  if  one  row  of  odontoblasts 
after  another  were  to  be  converted  into  basis-substance. 

"  As  to  the  first  question,  we  are  unable  to  give  a  positive 
answer,  but  take  it  for  granted  that  the  response  should  be 
affirmative,  and  that  the  odontoblasts  are  a  prerequisite  to  the 
formation  of  dentine.  We  often  see,  at  the  summit  of  the 
papilla,  medullary  tissue  bordering  the  already-formed  dentine 
without  a  trace  of  odontoblasts.  Through  the  researches  of 
John  Tomes,  we  know  that  the  odontoblasts  originate  in  the 
coalescence  of  medullary  corpuscles  of  the  papillarv  tissue; 
and  we  know,  furthermore,  that  the  odontoblasts  again  return 
to  the  medullary  condition  before  becoming  infiltrated  with 
lime-salts.  It  appears  possible  that  previous  odontoblasts  have 
been  transformed  into  medullary  tissue,  and  no  new  ones  pro- 
duced at  that  particular  period. 

"  To  the  second  question,  whether  or  not  the  odontoblasts  form 
a  single  row  for  the  time  being,  thus  involving  au  interruption 
in  the  appearance  of  the  basis-substance  of  the  dentine,  a  positive 
answer  can  be  given,  in  accord  with  the  observations  of  Kolli- 
ker  in  1852,  above  quoted.  The  difference,  however,  between 
his  views  and  ours  is,  in  our  judgment,  sufficiently  marked  to 
demand  attention. 


142      THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH. 

"  lie  declares  that  there  is  hut  one  row  of  odontohhists  capable 
of  producing  dentine,  and  that  these  become  continuous  by  a 
proliferation  of  the  nuclei  of  the  original  single  row.  He  dis- 
tinctly denies  that  the  pulp  as  a  whole  can  be  converted,  layer 
after  layer,  into  odontoblasts.  We,  on  the  contrary,  agree  with 
John  Tomes  in  the  view  that  the  medullary  corpuscles  of  the 
papillary  tissue  are  progressively  converted  into  odontoblasts, — 
a  view  which  explains  the  fact  that,  with  the  advancing  growth 
of  the  dentine,  the  bulk  of  the  papilla  diminishes.  We  add 
another  point, — viz,  that  each  odontoblast,  while  being  reduced  to 
medullary  corpuscles  at  its  distal  or  jperipheral  end,  is  being  added,  to 
by  an  attachment  of  medullary  coiyuscles  of  the  papillary  tissue  at 
its  proximal  or  central  end. 

"  Undoubtedly  there  are  periods  of  comparative  rest,  in  which 
a  fhllv-developed  odontoblast  borders  the  dentine,  and  dips  into 
the  papillary  tissue  with  sharply-defined  contours,  with  its  nar- 
row and  pointed  end.  As  soon,  however,  as  the  building  of 
dentine  is  resumed,  the  peripheral  end  of  the  odontoblast  is  seen 
to  have  di^uded  itself  into  medullary  bodies  again,  and,  simul- 
taneously, rows  of  medullary  corpuscles  are  superadded  to  the 
opposite  or  central  end. 

"  A  beautiful  illustration  of  this  process  may  be  seen  in  the 
developing  tooth  of  a  pig's  foetus,  ten  centimeters  long.  (See  Fig. 
85.)  Here  we  see  several  rows  of  odontoblasts,  bordering  the 
non-calcified  portion  of  the  basis-substance  of  the  dentine.  At 
that  portion,  in  which  unchanged  odontoblasts  stand  against  the 
dentine,  others  are  attached  to  the  uppermost  row,  likewise  in 
full  development.  This  we  consider  as  a  condition  of  compar- 
ative rest.  At  that  portion,  on  the  contrary,  in  which  the 
odontoblasts  are  replaced  by  medullary  corpuscles  toward  the 
dentine,  Avithout  a  distinct  boundary -line  between  the  two,  we 
see  rows  of  medullary  corpuscles  attached  to  the  inner  ends  of 
the  odontoblasts,  whereby  the  transverse  diameter  of  the  odonto- 
Idastic  layer  is  noiiceably  broadened.  In  the  former  instance, 
the  layer  of  odontoblasts  is  fairly  well  marked  toward  the  pap- 
illary tissue ;  in  the  latter  instance  it  is  indistinct,  the  odonto- 
blasts blending  with  the  papillary  tissue. 

"■  High  powers  of  the  microscope  still  better  illustrate  this  view. 
(See  Fig.  86.)  At  the  same  time  it  becomes  evident  that  the  den- 
tinal fibers,  originally  attached  to  and  connected  with  the 
odontoblasts,  become  situated  between  the  medullary  corpuscles- 


DEVELOPMENT    OF    DENTINE. 


143 


±iiG.  85. 


BO 


Tooth  of  a  Pig's  Fcetus  10  Centimeters  Long. 

B,  D,  calcified  dentine  :  DC,  non-calcified  dentine  :  0,  row  of  odontoblasts,  partly  fully  formed, 
partly  forming  ;  M,  odontoblasts  broken  up  into  medullary  corpuscles  in  the  process  of  forma- 
tion of  dentine ;  P,  yascularized  myxomatous  tissue  of  papilla.    Magnified  4i!KJ  diameters. 


144  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


Fig.  86. 


DC^> 


DM 


Tooth  of  a  Pig's  Ecetus  10  Centimeters  Long. 

/>,  I>,  calcified  dentine  ;  DC,  non-calcified  dentine  ;  DM,  dentine  in  the  process  of  formation 
from  medullary  corpuscles;  0,  odontoblasts  in  multiple  rows,  spindle-shaped  elements  wedged 
in  between  the  broad  odontoblasts ;  M,  medullary  corpuscles  arisen  from  odontoblasts,  such 
corpuscles  also  attached  to  the  distal  ends  of  the  odontoblasts.    Magnified  1200  diameters. 


DEVELOPMENT    OF    DENTINE. 


145 


Fig.  87. 


Tooth  of  a  Humax  Fcetus  Six  Moxths  Old. 

B,  D,  calcified  and  stratified  dentine  :  DC,  DC,  non-calcified  dentine,  the  border  of  the  calci- 
fied dentine  being  marked  by  globular  formations :  (9,  odontoblasts  splitting  into  medullary 
corpuscles  toward  the  dentine,  and  showing  rows  of  such  corpuscles  at  the  distal  ends;  M, 
medullary  corpuscles  ready  for  the  transformation  into  basis-substance  of  dentine;  P,  P, 
myxomatous  tissue  of  papilla.    Magnified  600  diameters. 


11 


146  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


Fig.  88. 


Tooth  op  Human  Fcetus,  Setex  Months. 

D,D.  dentine  calcified;  DC,  non-calcified  basis-substance  of  dentine,  close  above  the  capil- 
lary blood-vessels  broadened  and  visibly  made  up  of  medullary  corpuscles  ;  C,  capillary  blood- 
vessel in  transverse  and  longitudinal  section  ;  M,  M,  medullary  corpuscles  ready  for  infiltration 
with  basis-substance  ;  MO.  MO,  medullary  corpuscles  a,rranged  in  rows  for  the  formation  of 
odontoblasts.    Magnified  1200  diameters. 


DEVELOPMENT  OF  DEXTINE.  147 

as  soon  as  tlie  former  are  converted  into  the  latter.  Wher- 
ever we  notice  rows  of  medullary  corpuscles  at  the  inner  ends 
of  the  odontoblasts,  delicate  fibrill',e  are  seen  coursing  between 
their  rows  or  groups. 

Since,  according  to  our  views,  the  myxomatous  basis-sub- 
stance of  the  papillary  tissue  is  supplied  with  living  matter,  the 
same  as  are  the  so-called  cells,  there  is  no  difficulty  in  explain- 
ing the  origin  of  new  protoplasmic  bodies  from  tbe  previous 
myxomatous  basis-substance,  for  the  benefit  of  continuous  addi- 
tions to  the  odontoblasts. 

The  facts  just  descriljed  are  well  illustrated  in  the  developing 
teeth  of  a  human  foetus  from  six  to  seven  months  old.  (See 
Fig.  87.) 

The  cusp  of  the  dentine  shows  stratification,  although  no 
odontoblasts  are  seen  at  the  summit  of  the  papilla.  At  the 
sides  of  the  cusps,  odontoblasts  make  their  appearance,  broken 
up  into  finely-granular  medullary  corpuscles,  toward  the  non- 
calcitied  basis-substance  of  the  dentine,  and  augmented  in  their 
bulk  by  rows  of  glistening,  almost  homogeneous,  medullary 
corpuscles,  toward  the  papillary  tissue.  Occasionally  we  meet 
with  a  basis-substance  of.  dentine  not  yet  calcified,  and  still  ex- 
hibiting its  composition  of  medullary  corpuscles.  (See  Fig.  88.) 

Upon  studying  this  specimen,  all  doubts  as  to  the  origin  of 
the  basis-substance  of  the  dentine  must  vanish.  All  previous 
attempts  at  explaining  how  the  odontoblasts  are  converted  into 
dentine  must  prove  futile  in  the  face  of  such  a  specimen. 
Although  we  admit  that  such  a  plain  instance  is  only  excep- 
tionally seen,  we  thought  it  to  be  so  instructive  and  so  con- 
vincing that  we  had  an  illustration  made  with  a  very  high  power. 
With  the  facts  advanced,  a  hitherto  mooted  question  seems  to 
have  found  solution. 

As  to  the  question  why  dentine  in  all  its  stages  of  develop- 
ment appears  to  be  a  continuous  mass,  and  but  exceptionally 
interrupted  by  marks  of  stratification,  the  explanation  is  that 
the  odontoblasts  themselves  are  continuous.  ISTot  that  the 
original  odontoblasts  are  preserved  and  augmented  from  the 
periphery  toward  the  center ;  but  all  that  is  converted  of  an 
odontoblast  into  dentine,  at  its  peripheral  portion,  is  made  good 
by  the  addition  of  medullary  corpuscles  at  their  central  ends 
or  portions,  from  the  tissue  of  the  papilla, — protoplasmic  bodies 
and  basis-substance,  both. 


148  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

CHAPTER   XV. 

DEVELOPMENT  OF  THE  ENAMEL.* 

The  history  of  the  development  of  the  tissues  of  the  teeth  is 
not  intelligible  on  the  basis  established  by  the  researches  of 
Remak.  According  to  this  oliserver,  the  epiblast  and  the 
hypoblast  are  epithelial  formations,  and  give  rise  to  epithelial 
tissues  and  their  derivations  only.  The  mesoblastis  connective 
tissue,  including  the  muscles,  the  blood-vessels,  and  the  lymph- 
vessels.  Early  investigators  in  embryology  were  embarrassed 
in  attempting  to  explain  the  origin  and  formation  of  the  central 
nervous  system  (brain  and  spinal  cord),  which  unquestionably 
has  its  origin  in  the  epiblast,  although  in  full  development  it 
contains  a  large  amount  of  connective  tissue,  and  blood-vessels,, 
which  are  intermixed  with  nerve-substance  proper,  such  as  the 
gray  substance,  the  ganglionic  corpuscles,  and  the  axis-cylin- 
ders. For  that  portion  of  the  e})iblast  which  gives  rise  to  the 
nerve-centers,  some  authors  have  proposed  the  name  "  neuro- 
epithelium."  This  would  imply  that  trom  an  original  epithe- 
lial structure,  tissues  may  arise  which  have  no  resemblance  to 
epithelia,  and  do  not  contain  any,  except  in  the  ventricular 
lining  of  the  brain  and  the  central  canal  of  the  spinal  cord. 
It  is  admitted,  therefore,  that  a  certain  portion  of  the  epithelium 
of  the  embryo  contains  protoplasm,  which,  in  turn,  becomes 
gray  substance,  forms  the  ganglionic  corpuscles  and  axis- 
cylinders,  as  well  as  the  investment  of  the  latter, — the  myelin 
or  nerve-fat, — and  the  perineurium  or  neuroglia,  which  all 
authorities  admit  to  be  a  delicate  fibrous  connective  tissue. 

The  history  of  the  development  of  the  enamel  likewise 
furnishes  striking  proofs  of  the  fact  that  the  theory  of  exclu- 
siveness,  so  tar  as  the  epiblast  is  concerned,  is  not  tenable.  We 
have  demonstrated  that  the  original  epithelial  cord  of  the 
enamel-organ  serves  for  carrving  a  certain  amount  of  buildino; 
material  into  the  depth  of  the  connective  tissue.  This  material, 
however,  loses  its  epithelial  nature  as  soon  as  it  gives  rise  to 
the  enamel-organ  proper,  which  is  myxomatous  connective 
tissue.     The  fact  was  established  that  the  tissue  termed  enamel 


*  "  Contributions  to  the  History  of  Development  of  the  Teeth."    By  C.  Heitz- 
mann  and  C.  F.  "W.  Bodecker.     The  Independejit  Pracfitioner,  vols,  viii  and  ix. 


DEVELOPMENT  OF  THE  EXAMEL.  149 

is  epithelial  in  its  origin  only,  and  that  it  is  changed  from  its 
original  character  ^^hortly  hefore  becoming  enamel  proper. 
We  must  admit  that  enamel  will  not  he  formed  unless  upon  an 
epithelial  basis,  the  epithelium  in  this  instance  being  the 
conveyer  of  the  protoplasm  from  which  enamel  originates. 
But  to  assert  that  enamel  is  an  epithelial  structure  throughout, 
wi  'uld  be  as  erroneous  as  to  call  the  brain  and  the  spinal  cord 
epithelial  structures. 

From  an  organo-genetic  point  of  view,  we  may  say  that  the 
outer  senses  of  the  animal  organism,  serving  for  perceptions 
from  the  outer  world,  are  formations  of  the  outer  investment 
of  the  animal,  its  epiblast.  The  brain,  being  the  most  highly 
perfected  organ  of  sensual  perception,  continuously  takes  its 
growth  from  the  epiblast.     The  same  may  be  said  of  the  teeth. 

Fig.  89. 


Human  Embryo  Six  Weeks  Old.    Fhoxtal  Sectiox. 

T,  tongue  ;  L,  lip  ;  B,  base  of  oral  cavity :  F,  furrow,  in  transverse  section,  funnel-shaped. 
Magnified  25  diameters. 

which,  in  some  lower  order  of  amphibious  organisms,  such  as 
Chelonia,  are  nothing  Init  horny  ledges,  or  a  thickening  of  the 
epithelium.  Even  at  the  height  of  development  their  growth 
is  continuous  from  the  epiblast,  and  they  are,  at  least  as  far  as 
the  enamel  is  concerned,  derivations  from  it. 

Let  us  now  consider  the  direction  taken  by  the  epithelial 
cord  of  the  enamel-organ  into  the  depth  of  the  connective 
tissue,  up  to  the  time  when  the  enamel-organ  is  ready  for  the 
formation  of  the  enamel.  The  first  trace  of  the  future  tooth 
in  the  human  embryo  is  visible  about  the  sixth  week  of  intra- 
uterine life,  when  the  epithelium  of  the  oral  cavity  is  as  yet 
little  developed.  Here  we  notice  a  furrow,  which  is  situated 
close  behind  the  lip,  and  is  succeeded  by  an  elevation  of  medul- 
lary tissue.     (See  Fig.  89.) 


150 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


After  this  period  follows  the  formation  of  an  epithelial  peg, 
appearing  not  at  the  bottom  of  the  primitive  dental  furrow, 
but  at  some  distance  from  the  latter.  This  peg  appears  as  a 
reduplication  of  the  epithelial  layer  covering  the  elevation 
behind  the  furrow.     (See  Fig.  90.) 

Shortly  afterward,  the  epithelial  hill  has  gained  in  height 
considerably,  and  from  the  point  which  connects  the  hill  with 


Fig.   90. 


Base  of  Oral  Cavity  op  Human  Embryo  Two  Months  Old.    Feontal  Section. 
T,  tongue ;    L,  lip ;  B,  base  of  oral  cavity  ;  F,  furrow ;  EH,  epithelial  hill ;  EP,  epithelial 
peg.    Magnified  25  diameters. 

Fig.  91. 
o 


Base   op  Oral  Cavity  op  Human  Embryo  Two  and  a  Half   Months  Old.    Frontal 

Section. 
EH,  epithelial  hill ;  0,  epithelial  lining  of  base  of  oral  cavity ;  F,  furrow  ;   EC,  epithelial 
cord  of  enamel-organ  ;  EO,  club-shaped  enlargement  of  the  epithelial  cord,  the  future  enamel- 
organ.    Magnified  25  diameters. 

the  rest  of  the  oral  epithelium,  the  original  peg  has  elongated 
into  an  epithelial  cord.  A  striking  feature  of  this  cord  is  that 
from  its  periphery  arise  blunt  or  slightly-pointed  offshoots, 
while  at  the  same  time  its  distal  end  is  noticeably  broadened, 
the  epithelia  being  arranged  in  radiating  tracts  throughout, 
but  most  markedly  in  the  club-shaped  enlargement  of  the  distal 
end.     (See  Fig.  91.) 


DEVELOPMENT    OF    THE    EXAMEL. 


151 


In  the  third  month  of  embryonal  life,  the  epithelial  hill  still 
remains  a  prominent  formation.  From  the  point  of  its  junc- 
tion with  the  other  epithelium  arises  the  epithelial  cord,  which 
varies,  to  some  extent,  both  in  width  and  in  its  course.  Some- 
times the  cord  runs  nearly  parallel  with  the  base  of  the  oral 
cavity,  becoming  devious  on  the  way  to  its  club-shaped  distal 
end.  Its  periphery  is  slightly  fluted,  and  from  its  lower  contour 
arise  scanty  but  strongly-marked  epithelial  oftshoots,  the  signi- 
ficance of  which  is  not  perfectly  plain.  "We  may  assume  that 
a  large  secondary  oftshoot  forms  the  epithelial  cord  of  a  future 
permanent  tooth,  but  as  to  the  significance  of  the  short  second- 
ary oftshoots  we  can  only  suggest  that  the  epithelium  primarily 

Fig.  92. 


Base  of  Oral  Cavity  of  a  Humax  Embryo  Three  Months  Old. 

£3.  epithelial  hill :  F,  furrow,  sharply  marked  and  lined  by  a  heavy  layer  of  flat  epithelium  ; 
0,  base  of  oral  cavity  ;  EC,  epithelial  cord  ;  £0,  club-shaped  end  of  the  epithelial  cord,  the 
future  enamel-organ  ;  S,  secondary  oflfshoot ;  SP,  secondary  offshoot,  possibly  a  germ  of  the 
permanent  tooth  ;  P,  papilla.    Magnified  25  diameters. 


producing  the  cord  at  first  assumed  a  direction  which  afterward 
was  changed.  This  much  is  certain,  that  such  short  secondary 
offshoots  perish  and  disappear  in  the  course  of  farther  develop- 
ment. It  woidd  certainly  be  a  bold  hypothesis  to  consider  all 
such  short  secondary  oftshoots  germs  of  supernumerary  teeth,  or 
of  third  dentitions.  They  are  too  common  as  compared  with  the 
rare  cases  in  which  supernumerary  teeth  are  found.  At  this 
stage  of  development  the  first  trace  of  the  papilla  (the  future 
dentine)  is  noticeable.     (See  Fig.  92.) 

Sometimes  the  epithelial  cord  is  broad,  exhibiting  compara- 
tively few  blunt  secondary  ofiishoots.     Its  course  is  more  or  less 


152 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


vertical,  into  the  depth  of  the  connective  tissue  of  the  jaw. 
The  epithelium  within  the  cord  is  arranged  into  groups  sepa- 
rated by  trabeculae  somewhat  resembling  those  of  true  myxoma- 
tous connective  tissue.  The  club-shaped  end  of  such  a  cord  at 
this  period  shows  a  slight  separation  of  the  columnar  epithelium 
into  an  outer  and  an  inner  layer,  whereas  the  center  of  the  club- 
shaped  enlargement  is  occupied  by  medullary  corpuscles,  which 
as  yet  do  not  exhibit  the  characters  of  a  myxomatous  reticulum. 
Unquestionably,  tliis  medullary  tissue  has  arisen  from  epithelia, 
which  originally  filled  the  club-shaped  end  of  the  cord,  and  it  is 

Fig.  93. 


Floor  of  Oral  Cavity  of  a  Human'  Embryo  Three  Months  Old. 

EH,  epithelial  hill ;  F,  furrow;  0,  oral  epithelium ;  EC,  epithelial  cord :  S,  short  secondary 
oflfshoot;  EO,  medullary  tissue  of  enamel-organ;  P,  papilla,  detached.  Magnified  25 
diameters. 


this  medullary  tissue  from  which,  soon  afterward,  the  myxoma- 
tous reticulum  of  the  enamel-organ  proper  originates.  (See 
Fig.  93.) 

We  found  an  epithelial  cord  of  a  three-months'  embryo  pre- 
senting points  of  interest,  since  it  showed  e^ddences  of  the 
germ  of  a  temporary  molar.  A  short  offshoot  arose  at  the 
place  of  origin  of  the  epithelial  cord,  while  the  latter  made  a 
few  shallow  convolutions  and  then  abruptly  turned  downward 
in  a  direction  almost  at  right  angles  to  its  former  course. 

At  the  place  of  the  turn  a  broad  epithelial  laj^er  was  per- 
ceptible, showing  the  rather  thin  epithelial  tracts  before  alluded 


DEVELOPMENT    OF    THE    EXAMEL, 


153 


to,  and  in  part,  toward  the  adjacent  mednllary  tissue,  indis- 
tinctly bordered.  Tlie  club-shaped  end  of  the  epithelial  cord 
was  divided  into  two  segments  by  an  intervening  deep  fissure. 
The  broadest  segment,  again,  showed  blunt  protuberances,  to 
which  corresponded  shallow  hills  of  the  subjacent  papilla. 
The  club  admitted  of  an  indistinct  differentiation  into  an  ex- 
ternal and  internal  epithelium,  whereas  its  center  exhibited  a 
few  faint  tracts  of  epithelia  and  a  large  amount  of  medullary 
tissue,  which  as  yet  had  nowhere  begun  the  formation  of  a 
myxomatous  reticulum.     (See  Fig.  94.) 

When  the  embryo  has  reached  about  the  fourteenth  week, 

Pig.  94. 


Base  of  Deal  Cavity  of  a  Humax  Embryo  Threk  Months  Old. 

£'£r,  epithelial  hill;  /'.furrow:  0,  oral  epithelium:  EC,  epithelial  cord  of  enamel-organ; 

-S',  short  secondary  offshoot ;  SP,  broad  secondary  offshoot,  possibly  the  germ  of  a  permanent 

molar;  EO,  dub  of  the  epithelial  cord  filled  with  medullary  tissue  (the  future  enamel-organ) ; 

P,  papilla.    Magnified  25  diameters. 

the  epithelial  cord  is  of  special  interest,  on  account  of  the  ap- 
pearance of  two  distinct  layers  at  its  distal  end,  the  internal 
and  the  external  epithelium,  between  which  the  myxomatous 
enamel-organ  makes  its  appearance.  The  papilla,  at  this  point 
of  development,  has  a  distinct  neck,  being  of  a  mushroom 
shape.  At  its  distal  periphery  it  is  bordered  by  a  thin  layer  of 
fibrous  connective  tissue  extending  upward  along  the  external 
epithelium  to  a  certain  height,  and  producing  what  has  been 
termed  the  follicle,  or  tooth-sac.  In  one  of  our  specimens  the 
epithelial  cord  emanates  with  a  broad  base  from  the  epithelial 


164 


THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


liill,  having  at  this  point  several  short  and  bkmt  oiishoots 
directed  downward.  Its  general  course  is  almost  parallel  to  the 
floor  of  the  mouth.  The  enamel-organ  originates  from  its  distal 
end  in  an  abrupt  rectangular  manner,  with  a  somewhat  narrow 
neck.  The  external  epithelium  extends  into  a  solid  peg,  with 
a  slight  sigmoidal  curvature,  obviously  the  germ  of  the  future 
permanent  tooth.     (See  Fig.  95.) 

In  another  specimen  of  the  same  period,  the  epithelial  cord 
arises  from  the  base  of  the  epithelial  hill,  with  a  narrow  neck, 
in  immediate  connection  with  a  solid  epithelial  peg,  running  a 
downward  vertical  course,  with  a  slight  sigmoidal  curvature. 
The  epithelial  cord  itself  shows  blunt  offshoots  upward  as  well 
as  downward,  the  former  being  characterized  by  a  distinct  con- 
centric arrangement  of  their  epithelia.     The  general  course  of 

Fig.   95. 


Base  of  Oral  Cavity  of  a  Human  Embeyo  Three  and  a  Half  Months  Old. 
EH,  epithelial  hill :  0,  oral  epithelium ;  EC,  epithelial  cord ;  SP,  secondary  offshoot  of  a 
permanent  tooth,  arising  from  the  external  epithelium  of  the  enamel-organ  ;  EO,  enamel- 
organ  of  a  distinctly  myxomatous  character ;  P,  papilla ;  F,  follicle.     Magnified  25  diameters. 

the  epithelial  cord  is  slightly  downward.  Its  cup-shaped  distal 
end  is  marked,  by  three  prolongations,  the  concavities  of  which 
correspond  to  two  myrtle-leaf-shaped  papillae.  Evidently,  this 
is  the  germ  of  a  future  temporary  molar.  No  trace  of  a  corre- 
sponding permanent  tooth  was  visible  at  the  distal  end  of  the 
epithelial  cord.  The  external  epithelium  is  very  broad,  and 
visible  only  along  the  broad  cup.  The  enamel-organ  is  narrow,, 
but  possesses  a  pronounced  mjTfomatous  structure.  (See  Fig. 
96.) 

The  fourth  month  of  embryonal  life  differs  from  the  previous 
stage  only  as  the  myxomatous  enamel-organ  gains  considerably 
in  volume,  with  a  simultaneously-marked  differentiation  into 
its  two  boundary  layers,  the  external  and  the  internal  epithe- 
lium.    The  papilla,  at  this  stage,  likewise,  has  gained  in  bulk^ 


developme^:t  of  the  enamel. 


155 


and  its  enveloping  layer  of  fibrous  connective  tissue  extends 
farther  up  along  the  convexity  of  the  cup  of  the  enamel-organ. 
In  one  of  the  specimens,  the  epithelial  hill  is  extremely  marked, 
and  contains  a  central  vacuole,  possibly  the  first  step  toward  its 
destruction,  since  shortly  afterward  no  trace  of  it  is  found. 


Tig.  96. 


Floor  of  Oral  Cayitt  of  a  Hdiax  Embryo  Three  and  a  Half  Months  Old. 
EH,  epithelial  hill :  0,  oral  epithelium ;  EC,  epithelial  cord  of  enamel-organ ;  SP,  second- 
ary offshoot,  possibly  the  germ  of  the  permanent  tooth  ;  EO,  enamel-organ  ;  P^  and  P^,  double 
papilla ;  F,  follicle.    Magnified  25  diameters. 

Fig.  97. 


Floor  of  Oral  Catity  of  a  Human  Embryo  Four  Months  Old. 
EH,  epithelial  hill ;  0,  oral  epithelium ;  EC,  epithelial  cord  with  numerous  offshoots ;  SP, 
secondary  peg  of  permanent  tooth  ;  EO,  myxomatous  enamel-organ  :  P,  papilla  :  F,  follicle . 
Magnified  25  diameters. 

The  epithelial  cord  begins  with  a  narrow  neck,  and  has  numer- 
ous oblique  secondary  offshoots,  mainly  at  its  upper  periphery. 
The  arrangement  of  the  epithelia  into  tracts  is  marked  along 
the  epithelial  cord,  not  only  of  the  temporary  but  also  of  the 
permanent  tooth.     (See  Fig.  97.) 


156  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

In  another  specimen  of  the  same  age,  the  epithelial  hill  is 
absent.  The  cord  has  but  a  limited  number  of  offshoots,  some 
of  which  are  pediculated,  and  some  have  the  shape  of  a  lancet. 
The  peg  of  the  permanent  tooth  is  conspicuous  by  its  devious 
course,     (See  Fig.  98.) 

When  the  embryo  is  at  the  age  of  four  and  a  half  months, 
the  development  of  the  enamel-organ  has  still  further  pro- 
ceeded: its  myxomatous  tissue  is  plainly  marked,  and  the 
papilla  has  correspondingl}'  gained  in  bulk.  The  specimen 
illustrated  is  noteworthy  for  its  short  vertical  epithelial  cord, 
which  is  directly  in  connection  with  the  lining  epithelium  of 
the  oral  cavity.  The  secondary  offshoots  are  but  short,  and  no 
trace  of  a  peg  for  the  permanent  tooth  is  visible  in  this  section. 
The  cup  of  the  enamel-organ  is  lobulated,  evidently  belonging 
to  a  future  molar.     (See  Fig.  99.) 

The  next  question  to  be  considered  is,  How  does  epithelium 
grow  from  an  originall}'  small  point  into  a  comparatively  long 
epithelial  cord  ?  Most  observers  agree  that  epithelium  has  an 
independent  growth,  and  that  its  elements  by  division  and 
multiplication  will  produce  epithelium,  and  no  other  tissue. 
During  the  last  fourteen  years  many  microscopists  have  studied 
the  so-called  indirect  division  of  "  individual  cells,"  which 
became  traceable  after  the  application  of  certain  reagents, 
especially  safranine.  This  dye  rendered  visible  a  filamentous 
structure  in  the  nucleus,  apparently  independent  of  the  sur- 
rounding protoplasm,  which  did  not  take  up  the  stain  of  the 
safranine.  The  filaments  produced  beautiful  star-shaped  figures, 
with  equatorial  divisions  leading  to  a  fission  of  the  original 
nucleus,  and  the  process  has  been  termed  Jiaryokinesis  or  mitosis. 

In  fresh  specimens,  or  those  preserved  in  a  chromic-acid  solu- 
tion, the  filamentous  structure  of  the  nucleus  does  not  exist,  or, 
at  least,  is  not  plainly  visible,  although  Bizzozero,  of  Italy, 
<3laimed  that  safranine  will  bring  out  the  filamentous  structure 
of  the  nucleus  even  in  chromic-acid  specimens.  The  filaments 
taking  up  the  dye  were  termed  chromatin,  and  all  those  remain- 
ing pale,  achromatin;  and  it  was  claimed  that  these  were  two 
different  substances.  Considering  the  fact  that  the  filaments 
are  produced  only  by  certain  reagents,  we  should  be  loth  to 
assume  that  the  structure  thus  rendered  visible  really  corre- 
sponds to  the  unstained  and  living  epithelium.  The  doubts 
become  still  stronger,  if  we  recall  the  fact  that  living  matter  is 


DEVELOPMENT    OF    THE    EXAMEL. 
Fig.  98. 


157 


Floor  of  Oral  Cavity  of  a  Human  Embryo  Four  Months  Old. 

0,  oral  epithelium ;  EG,  epithelial  cord  ;  S,  short  pediculated  offshoot ;  5,5,  secondary  off- 
shoot, lancet-shaped  ;  SP,  secondary  peg  of  permanent  tooth  :  EO,  enamel-organ ;  P,  papilla ;. 
F,  follicle.    Magnified  25  diameters. 

Fig.  99. 


Examel-Orgax  and  Papilla  of  Human  Embryo  Four  and  a  Half  Months  Old. 

0,  oral  epithelium :   EC,  short  epithelial  cord ;  S,  secondary  offshoot ;   EO,  enamel-organ  : 
P,  papilla  ;  F,  follicle.    Magnified  25  diameters. 


158 


THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


stained  deeply  bj  the  same  reagent,  if  present  in  a  compact 
mass,  where  thin  layers  of  it  remain  unstained,  as  is  the  case  in 
the  protoplasm  which  surrounds  the  central  nucleus.  From 
this  point  of  view  the  terms  chromatin  and  achromatin  be- 
come superfluous,  especially  if  we  admit  that  the  living  matter 
during  life  is  in  constant  motion,  particularly  in  the  process  ot 
growth,  although  its  continuity  may  temporarily  be  interrupted. 
"V^^hat  we  see  in  a  growing  epithelial  cord,  with  high  powers 
of  the  microscope,  is  depicted  in  Fig.  100. 

Fig.  100. 


Epithelial  Cord  of  the  Examel-Orgax  of  a  Human  Embryo  Three  and  a  Half 

Months  Old. 

E,  epithelial  cord ;  C,  connective  tissue.    Magnified  800  diameters. 


We  observe  epithelia  along  the  borders  of  the  cord  which 
are  elongated  and  bear  the  name  of  columnar  epithelium ;  while 
the  central  portion  is  tilled  with  epithelia  which  exhibit  about 
an  ecjual  diameter  in  all, directions,  and  are  termed  cuboidal. 
Both  varieties  show  difterences  in  the  size  and  structure  of 
their  nuclei.  Some  nuclei  are  very  large  and  distinctly  reticu- 
lar, others  are  small  and  nearly  compact,  often  appearing  as  if 
split  up  into  several  lumps,  with  a  vacuole  or  plasmatic  space. 
Sometimes  a  nucleus  is  elongated  or  irregular  in  shape,  another 


DEVELOPMENT  OF  THE  EXAMEL.  159 

T)eing  globular  or  vesicular.  Again,  we  see  epithelia  much  en- 
larged, holding  in  their  interior  several  nuclei.  An  epithelium 
in  this  condition  has  been  termed  by  previous  observers  "  the 
mother  cell."  i^ot  infrequently  we  observe  solid,  spindle-shaped 
bodies  in  the  cement-substance,  between  two  epithelia.  All 
these  forms  become  intelligible  only  under  the  assumption  that 
epithelium  is  composed  of  proto[>lasm,  in  which  the  living- 
matter  greatly  varies  in  size  and  shape,  according  to  the  state 
of  growth  and  new  formation.  The  cement-substance  is  often 
absent,  and  thus  large  protoplasmic  masses  become  conspicuous, 
TV'ith  a  varying  number  of  nuclei.  Where  the  cement-substance 
is  present,  it  is  usually  traversed  by  radiating  lines,  which  are 
the  connecting  bridges  of  the  living  matter.  Again,  these 
lines  may  coalesce  into  solid  masses,  presenting  spindle,  pear, 
or  club  shapes,  from  which  new  epithelia  arise,  as  shown  by 
Louis  Elsberg. 

The  way,  therefore,  in  which  epithelium  grows  is  by  the 
augmentation  of  its  living  matter,  and  the  appearance  of  new 
cement-substance, — that  is,  new  lines  of  demarcation,  in  which 
process  the  continuity  of  the  living  matter,  though  temporarily 
interrupted  in  certain  foci,  in  the  whole  remains  preserved  and 
unbroken.  In  the  epithelial  cord  of  the  enamel-organ  the 
connecting  spokes  in  the  cement-substance  are  prominently 
marked  in  all  its  layers  and  stages  of  development. 

We  now  proceed  to  consider  the  changes  of  the  enamel-organ 
about  the  beginning  of  the  fifth  month.  If  we  examine  the 
cup-shaped  enlargement  of  the  enamel-organ  at  this  period,  we 
observe  a  distinctly-marked  border  composed  of  columnar  epi- 
thelia, whereas  the  interior  of  the  cup  is  filled  with  medullary 
corpuscles,  which,  in  the  center,  present  the  so-called  stellate 
reticulum.  At  the  end  of  the  fourth  and  the  beginning  of  the 
fifth  month,  we  invariably  find  some  epithelial  cords,  which,  at 
their  interior  ends,  are  broadened  and  contain  a  distinctly  marked 
stellate  reticulum.     (Fig.  101.) 

The  first  question  to  be  entered  into  is,  Whence  comes  the 
myxomatous  tissue  known  as  the  stellate  reticulum  in  the  inte- 
rior of  the  cup  ?  According  to  our  present  knowledge  of  the 
tissues  of  the  mammalian  organism,  we  are  entitled  to  call  the 
stellate  reticulum  a  myxomatous  tissue,  which  is  a  variety  of 
connective  tissue.  This  tissue  occurs  most  extensively  in  the 
embrvonal  organism,  and  remains  throuo^hout  life  in  the  fullv- 


160 


THE    AXATO.MY    AXD    PATHOLOGY    OF    THE    TEETH. 


developed  body  only  in  a  limited  number  of  organs,  sncli  as  the 
Xmlp  of  a  tooth,  the  hinph-ganglia,  and  the  so-called  adenoid 
tissue,  which  properly  ought  to  be  called  lymph-tissue,  and  is- 


Fig.  101. 


EE 


Epithelial  Cord  terminatin-g  ix  the  Examel-Orgax.   Human  Embryo  at  the  End  of 
THE  Fourth  or  the  Begixxixg  of  the  Fifth  Month  of  Intea-Uteeine  Life. 

0,  stratified  epithelium  of  the  oral  cavity;  TT,  epithelial  cord  of  temporary  tooth;  PT, 
epithelial  cord  of  permanent  tooth  ;  N,  epithelial  nests  and  buds  at  the  bottom  of  the  furrow 
and  along  the  cords  of  both  the  temporary  and  permanent  teeth  ;  .1/,  myxomatous  tissue  of  the 
enamel-organ  (stellate  reticulum);  EE,  external  i  outer)  epithelium;  IE,  internal  (inner) 
epithelium  ;  /,  intermediate  layer  between  inner  epithelium  and  myxomatous  tissue  ;  P,  papilla 
with  numerous  blood-vessels  :  E,  embryonal  or  medullary  tissue  crowded  with  medullary  cor- 
puscles at  a  certain  distance  from  the  epithelial  formation.    Magnified  50  diameters. 


DEVELOP.MEXT  OF  THE  EXAMEL.  161 

distributed  througiiont  the  mucous  membranes,  especially 
during  the  early  periods  of  life.  Unless  we  assume  that  the 
enamel-organ  is  a  tissue  entirely  different  from  all  others  enter- 
ing into  the  structure  of  the  body,  we  must  call  it  myxomatous 
connective  tissue. 

Those  who  adhere  strictly  to  the  teachings  of  Thiersch  and 
Waldeyer  will  l)e  loth  to  admit  that  epithelium  can  ever  change 
into  connective  tissue.  Researches  thus  far,  however,  have  led 
us  to  the  conviction  that  such  a  transformation  is  by  no  means 
impossible.  The  thyroid  gland,  for  instance,  is  originally  com- 
posed of  alveoli  lined  by  epithelia.  Shortly  after  birth,  how- 
ever, the  epithelium  is  replaced  by  a  medullary  or  lymph- 
tissue.  The  whole  central  nervous  system  (the  brain  and  spinal 
cord)  originates  from  the  embryonal  epiblast,  which  is  strictly 
epithelial  in  nature.  ^Nevertheless,  nobody  will  maintain  that 
the  central  nervous  system,  so  richly  supplied  with  blood-ves- 
sels, is  an  epithelial  structure,  except  in  the  lining  of  the  ven- 
tricles of  the  brain,  and  the  central  canal  of  the  spinal  cord. 
There  may  be  advocates  of  the  exclusive  nature  of  epithelial 
tissue  who  might  think  of  an  immigration  of  medullary  cor- 
puscles between  the  epithelia  of  the  enamel-organ  for  the  bene- 
fit of  the  formation  of  the  stellate  reticulum,  but  there  is  not 
the  least  indication  of  such  a  process  in  any  of  our  specimens. 
On  the  contrary,  we  can  prove  a  gradual  transformation  of  the 
epithelia  into  myxomatous  tissue. 

In  the  third  month  of  intra-uterine  life,  we  observe,  inside 
of  the  epithelial  cup  of  the  enamel-organ,  a  zone  entirely  occu- 
pied by  medullary  corpuscles,  and  even  in  the  fourth  and  fifth 
months  such  a  gradual  transition  is  distinctly  traceal)le  (Fig.  102). 

Those  who  still  adhere  to  the  cell  doctrine  will  never  l:)e  al)le 
to  understand  how  medullary  tissue  arises  ti'om  epithelia.  Ac- 
cording to  our  views,  however,  there  exist  no  individual  cells, 
but  layers  of  protoplasm,  in  which  the  living  matter  is  dis- 
tributed in  a  reticular  arrangement.  Every  particle  of  the 
li^^ng  matter  is  able  to  grow  from  the  size  of  a  minute  granule 
to  that  of  a  solid  lump,  in  which  afterward  takes  place  a  dif- 
ferentiation into  a  peripheral  protoplasm  containing  compara- 
tively little  living  matter,  and  a  central  body,  termed  nucleus, 
with  a  larger  amount  of  li^ing  matter. 

The  inner  epithelia,  at  the  period  mentioned  above,  exhibit 
augmented  nuclei  and  small  glistening'granules  near  the  fold, 

12 


162  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

Fig.   102. 


EE 


EM 


Lower  Edge  of  the  Cup  of  the  Exajiel-Orgax,  showing  the  Recurvation  of  the- 
External  into  the  Internal  Epithelium,  at  the  End  of  the  Fourth  Month  of 
Ixtra-Uterine  Life. 

EM,  embryonal  or  medullary  tissue ;  EE,  external  epithelium,  composed  of  cuboidal  epi- 
thelia ;  T,  cuboidal  epithelia  turning  into  columnar  epithelia :  IE.  inner  epithelium  breaking- 
down  into  medullary  tissue  and  giving  rise  to  the  spindles  composing  the  intermediate  layer, 
close  above  the  internal  epithelium  :  M,  myxomatous  tissue,  or  stellate  reticulum,  bounded 
toward  the  external  and  internal  epithelium  by  the  intermediate  layer,  and  continuous  with  the- 
medullary  tissue  filling  the  border  of  the  cup  ;  P,  papilla.    Magnified  500  diameters. 


Fig.  103. 


Inner  Epithelium   or  the   Enamel-Organ   of  a  Human    Embryo  of  Four  Months  of 

Intra-Uterine  Life. 

E,  inner  epithelia  connected  with  each  other  by  delicate  thorns,  traversing  the  cement-sub- 
stance. In  their  interior  vacuoled  lumps  are  seen  of  greatly  varying  sizes,  which  toward  the 
enamel-organ  are  split  up  into  smaller  reticulated  corpuscles,  all  being  interconnected  by  deli- 
cate offshoots  ;  /.intermediate  layer  composed  of  spindle-shaped  medullary  corpuscles;  M,. 
beginning  formation  of  the  myxomatous  reticulum,  in  the  meshes  of  which  we  observe  nucle- 
ated protoplasm.    Magnified  1200  diameters. 


DEVELOPMENT  OF  THE  EXAMEL,  163 

corresponding  in  position  to  the  neek  of  the  fntnre  tooth.  The 
more  we  turn  to  the  center  of  the  cup,  the  more  shall  we  be 
struck  by  the  presence  of  glistening  homogeneous  lumps  in  the 
epithelia,  until  we  have  reached  the  center  of  the  cup,  where 
we  observe  that  epithelium  has  been  transformed  into  a  number 
of  such  lumps  in  a  regular  arrangement,  which  reminds  us  of 
their  origin  from  previous  epithelia.  The  original  epithelia 
gradually  become  enlarged,  and  at  last  are  split  up  into  a 
number  of  medullary  corpuscles.  As  a  rule,  this  process  of 
transformation  is  most  marked  in  the  original  epithelia  at  the 
portion  directed  toward  the  stellate  reticulum,  whereas,  in  that 
portion  nearest  the  papilla,  the  epithelial  character  ma}^  still  be 
preserved,     (Fig.  103.) 

The  medullary  corpuscles  first  assuming  a  spindle  shape, 
constitute  the  intermediate  layer  {stratum  i/itermediu/n).  The 
innermost  spindles  are  in  connection  with  a  comparatively 
coarse  net-work,  representing  the  first  trace  of  the  stellate  re- 
ticulum. The  trabeculsB  of  this  reticulum  are  composed  of 
solid  or  vacuoled  spindles,  inclosing  spaces  which  appear  to  be 
filled  with  a  distinctly  reticulated  protoplasm,  holding  central 
nuclei.  The  latter  exhibit  a  varying  number  of  coarser  gran- 
ules, the  so-called  nucleoli. 

Xot  infrequently  the  intermediate  layer  is  missing,  which 
fact  affords  the  best  opportunity  for  observing  the  gradual 
transition  of  the  homogeneous  globules  arising  from  the  epi- 
thelia into  nucleated  protoplasmic  bodies,  and  finally  into  the 
myxomatous  reticulum.  Changes  similar  to  those  described 
take  place  in  the  central  portions  of  the  external  epithelia,  and, 
as  it  seems,  even  precede  the  changes  of  the  inner  epithelia. 
Thus  the  original  columnar  bodies  of  the  outer  epithelium  are 
reduced  to  a  row  of  cuboidal  epithelia,  as  seen  in  Fig,  102,  ^E. 
The  medullary  corpuscles  are  slightly  enlarged ;  their  nuclei, 
at  first  plainly  visible,  are  likewise  split  up  into  a  delicate  re- 
ticulum, and  both  become  infiltrated  with  a  myxomatous  basis- 
substance.  The  peripheral  portions  of  the  original  medullary 
corpuscles,  on  the  contrary,  are  solidified  into  nucleated  forma- 
tions of  living  matter,  representing  the  stellate  reticulum  proper. 
The  meshes  of  the  myxomatous  tissue  in  the  stellate  reticulum 
are  originally  small,  and  correspond  in  size  to  the  medullary 
corpuscles,  from  which  they  arose.  The  corpuscles  of  the 
stellate  reticulum  are  mostly  solid.        ater,  several  medullary 


164 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


corpuscles  are  required  for  tlie  formation  of  a  large  field  of 
basis-substance.  The  original  stellate  reticulum,  in  this  view, 
must  fall  back  to  an  embryonal  or  medullary  tissue  before 
changing  into  a  more  perfect  myxomatous  tissue,  such  as  we 
observe  from  the  end  of  the  fifth  month  of  foetal  life  up  to  the 
full  development  of  the  enamel.     (Fig.  104.) 

Toward  the  end  of  the  fourth  and  the  beginning  of  the  fifth 
month,  the  stellate  reticulum  is  composed  of  nucleated  proto- 
plasmic bodies,  with  a  varj-ing  number  of  branching  and  inter- 
connecting offshoots.  With  low  powers  of  the  microscope,  the 
basis-substance  in  the  meshes,  inclosed  l)y  the  corpuscles  and 

Tig.  104. 


Stellate   Reticulum,  or  Myxomatous  Tissue,  of  the   Enamel-Organ  of   a    Human 
Foetus  of  Five  Months  of  Intra-Uterine  Life. 

Magnified  1200  diameters. 


their  offshoots,  appears  to  be  homogeneous  and  structureless. 
The  highest  powers,  however,  reveal  in  this  basis-substance  the 
presence  of  a  delicate  reticular  structure,  even  without  the 
addition  of  any  reagent.  This  structure  has  arisen  by  a  direct 
transformation  of  the  original  medullary  corpuscles  into  basis- 
substance.  In  the  highest  development  of  the  stellate  reticulum, 
such  as  seen  in  the  seventh  and  eighth  months  of  foetal  life,  the 
nucleated  corpuscles  are  more  slender,  and  the  reticulum  is  com- 
posed mainly  of  delicate  branching  and  interconnecting  fibers. 
The  further  changes  of  the  external  epithelium  are  of  con- 


DEVELOPMENT    OF    THE    EXAMEL. 


165 


siderable  interest.  While  about  the  fourth  month  of  intra- 
uterine life  the  inner  portions  of  the  external  epithelium  are, 
as  mentioned  above,  transformed  into  medullary  tissue  and 
participate  in  the  formation  of  the  myxomatous  enamel-organ, 
a  single  row  of  cul)oidal  epithclia  is  left.     From  the  remains  of 

Fi<     105 


Budding   of   the   Extern  i.L   Epithjlium     f   the  E\ -imel  Ortw  of  i  Human  F(etus 

Seven  Momhs  Old. 

M,  myxomatous  reticulum  of  the  enamel-orgm  ;  C,  delicate  fibrous  connective  tissue :  E, 
epithelial  bud  arisen  from  the  external  epithelium;  P,  large  protoplasmic  body  filled  with 
glistening  coarse  granules  ;   B,  newly-formed  blood-vessel.    Magnified  500  diameters. 


this  external  epithelium,  a  new  growth  takes  place,  of  a  markedly 
centrifugal  character.  By  a  multiplication  of  the  epithelial 
elements,  solid  buds  and  knobs  are  formed,  well  known  to  pre- 
vious observers.     (Fig.  105.) 


166  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

The^se  l)uds  are  at  first  in  continuity  with  the  external  epithe- 
lium, and  have  a  distinct  layer  of  outer  columnar  and  a  varying 
number  of  inner  layers  of  cuhoidal  epithelia.  They  are 
characterized  by  a  brownish  color,  common  to  all  epithelial 
formations.  "We  observe  that,  both  in  the  central  portions  of 
these  buds  and  along  the  original  row  of  the  external  epithe- 
lium, a  transformation  takes  place  into  medullary  corpuscles, 
the  same  as  we  observe  toward  the  myxomatous  enamel-organ. 
This  medullary  tissue  develops  into  connective  tissue  of  a 
decidedly  fibrous  character.  Thus  we  oliserve  numerous  inter- 
ruptions in  the  external  epithelium,  partly  filled  with  medul- 
lary and  partly  with  fibrous  connective  tissue.  The  latter  is  in 
direct  connection  with  the  myxomatous  reticulum,  or  this  con- 
nection is  established  by  spindle-shaped  corpuscles,  resembling 
those  of  the  intermediate  layer  close  above  the  internal  epithe- 
lium. 

At  the  time  when  the  buds  sprout  from  the  external  epithe- 
lium, an  active  new  formation  of  blood-vessels  and  blood- 
corpuscles  takes  place  in  the  immediate  vicinity  of  the  buds. 
At  first  we  notice  large  protoplasmic  bodies  with  coarse  gran- 
ules, which  were  known  to  Theodore  Schwann,  in  1839,  by  the 
name  of  blood-cells.  With  the  increase  of  the  size  of  tliese 
bodies,  the  granules  likcAvise  become  coarser,  and  assume  the 
properties  of  the  so-called  haematoblasts.  Tliese  grow  up  to 
the  size  of  red  blood-corpuscles,  and  we  not  infrequently  en- 
counter in  the  bays  between  the  buds,  groups  of  h^ematoblasts, 
or  fully-developed  blood-corpuscles,  apparently  isolated  and  in 
no  connection  with  blood-vessels.  At  last,  capillary  l)lood- 
vessels  arise  from  the  conference  of  blood-cells,  which  are  filled 
with  red  blood-corpuscles.  The  splitting  of  the  external  epithe- 
lium into  isolated  buds  and  nests  of  an  epithelial  character  is 
especially  marked  near  the  neck  of  the  future  tooth.  (Fig.  106.) 
At  this  place  the  amount  of  myxomatous  enamel-organ  in  a 
seven-months  foetus  is  usualh*  small,  since' a  great  quantity 
of  it  has  already  been  transformed  into  enamel-tissue.  But 
even  here  a  few  small  and  isolated  epithelial  nests  are  seen,  sur- 
rounded by  a  large  numljer  of  capillary  blood-vessels,  filled  with 
blood-corpuscles.  It  is  evident  that  all  these  blood-vessels 
are  newly  formed,  and  indeed  we  can  trace  the  formation  of 
blood-vessels  in  this  situation  step  by  step.  Even  the  myxo- 
matous trabeculse  of  the  enamel-organ  participate  in  the  forma- 


DEVELOPMENT    OF    THE    ENAMEL. 


167 


tioii  of  capillaiy  blood-vessels.  "We  liave  seen  closed  spaces,  or 
vesicles,  sprung  from  the  basis-substance  of  the  myxomatous 
tissue,  filled  with  liaematoblasts  and  red  blood-corpuscles,  partly 
in  connection  with  already-formed  or  forming  capillaries,     ^o 


Fig.  106. 


I-BV 


LE 


LE 


Isolated  EpiiHELiii  Nests,  of  the  Plvce  or  the   Ewmel  Oec  a_\  c   rrespondixg  to 
THE  Neck  cf  the  Fiture  Tioth  of  a  Hlman  Fcetls  Se^e\  M  nths  Old. 

M,  my.xomatous  reticulum  of  the  enamel-organ ;  J.,  row  of  ameloblasts  ;  /,  intermediatelayer 
composed  of  spindles  and  fibers  ;  B,  vesicle  filled  with  haematoblasts  and  red  blood-corpuscles  ; 
V,  capillary  blood-vessel  forming  from  trabecular  of  the  myxomatous  reticulum  :  B  V,  irregular 
spaces  filled  irith  ha?matoblasts  and  red  blood-corpuscles,  lined  by  endothelia  and  in  an  incom- 
plete connection  with  forming  capillaries  ;  EE,  epithelial  nests,  the  remnants  of  the  external 
epithelium.    Magnified  500  diameters. 

doubt  the  living  matter  inclosed  in  tire  basis-substance  has 
grown  into  hsematoblasts.  This  process  is  indicated  by  the 
appearance  either  of  coarsely-granular  or  of  compact  glistening 
nuclei  in  the  meshes  of  mvxomatous  reticulum. 


168 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


Wherever  we  observe  epithelial  nests,  they  are  invariably 
enlarged,  toward  the  enamel-organ,  by  spindles  and  fibers  of 
an  intermediate  layer.  Their  scarcity  and  diminutiveness  at 
the  place  corresponding  to  the  neck  of  the  tooth  indicate  that 
they  are  completelv  transformed  into  mednllary  tissue.  Con- 
sidering the  fact  that  at  the  end  of  the  intra-uterine  develop- 
ment the  enamel-organ  is  nearly  exhausted,  and  the  enamel 
which  is  formed  up  to  that  time  is  comparatively  thin,  there 
is  good  reason  for  the  assumption  that  the  medullary  tissue 


Dissolution  of  Epithelial  Cord  of  the  Examel-Orgax  into  Isolated  Clusters  of  a 
HuMAX  Fcetus  Five  Months  Old.    Horizontal  Section. 

C,  fibrous  connective  tissue  with  scanty  blood-vessels ;  iV,  epithelial  nest  composed  of  large, 
flat,  almost  epidermal-like  scales,  producing  onion-like  layers  around  the  central  group  ;  this 
nest  is  surrounded  by  tracts  composed  of  cuboidal  epithelium ;  E,  clusters  of  cuboidal  epi- 
thelia  holding  concentrically  arranged  epithelial  nests  ;  R,  remnants  of  epithelia  transformed 
into  clusters  of  medullary  corpuscles.    Magnified  100  diameters. 


Sprung  from  the  previous  external  epithelium  is  the  source  for 
the  completion  of  such  enamel  as  we  observe  upon  temporary 
teeth  when  they  emerge  from  their  sockets. 

Of  special  interest  are  concentrically  stratified  globular  nests 
and  buds,  in  which  the  epithelia  appear  flattened  and  arranged 
in  the  shape  of  an  onion.  Such  nests  are  often  lacking  alto- 
gether, and  sometimes  they  are  present  in  small  numbers  in 
the  center  or  at  the  periphery  of  the  epithelial  cord.     Some- 


DEVELOPMENT    OF    THE    EXAMEL. 


169 


times  their  number  is  very  large.  The  centers  of  the  nests  are 
occasionally  filled  with  globules  of  high  refraction,  possibly 
colloid  material  or  eleidin  (horn  tat).     In  some  specimens  the 


Fig.  108. 


FiKST-FoRMED  Dentii^k  axd  Enamel  of  Humax  FffiTus,  Sevex  Months. 

E.  enamel-cap ;  D,  calcified  dentinal  cap  ;  DD,  non-calcified  dentine  ;  0,  row  of  odontoblasts  ; 

P,  papilla,  with  blood-vessels ;  M,  stellate  reticulum  of  enamel-organ  ;  IE,  inner  epithelium  ; 

EE,  clusters  of  the  remains  of  the  outer  epithelium  ;  C,  fibrous  connective  tissue.    Magnified  50 

diameters. 

epithelial  structure  of  the  peg  is  little  marked,  especially  in 
places  where  the  epithelial  peg  produces  broadened  layers,  with- 
out sharp  contours  toward  the  surrounding  connective  tissue. 


170  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

In  such  places  tracts  are  seen  composed  of  ro^vs  of  solid  nuclei, 
or  solid  cords,  Itetween  which  line  granular  protoplasm  is  visi- 
ble. Such  tracts  have  been  repeatedly  alluded  to  in  the  descrip- 
tion of  the  early  forms  of  development  of  the  epithelial  cord 
of  the  enamel-organ.  It  is  quite  possible  that  in  such  places  a 
transition  takes  place  from  the  epithelial  to  the  medullary,  and 
from  this  to  connective  tissue.  This  is  rendered  probable  by 
the  fact  that  the  broadened  portions  of  the  epithelial  cord  have 
sharp  contours  only  on  one  side,  whereas  the  opposite  peripher}^ 
almost  blends  with  the  adjacent  connective  tissue,  without  a 
distinct  line  of  demarcation  l)etween  the  two  kinds.  While  we 
admit  that  the  original  epithelial  peg  and  cord  are  of  a  marked 
epithelial  structure,  at  the  same  time  Ave  claim  that  in  the 
advancing  process  of  growth  the  epithelium  does  not  retain  its 
speciiic  structure,  but  l)lends  with  or  is  transformed  into  connec- 
tive tissue.     (See  Fig.  107.) 

The  formation  of  enamel  commences  about  the  sixth  month 
of  foetal  life,  at  a  period  when  the  dentine,  which  begins  to  form 
about  the  tifth  month,  has  assumed  a  certain  thickness.  About 
the  seventh  month,  we  observe  at  the  summit  of  the  papilla  a 
comparatively  broad  cap,  the  dentine,  and  above  this  a  some- 
what narrower  layer  of  enameL     (Fig.  108.) 

Investigations  of  the  development  of  enamel  are  rendered 
difficult  by  the  fact  that  the  enamel-organ  is  almost  invariably 
found  to  be  detached  from  the  enamel  and  the  papilla.  This 
perplexity  may  be  obviated,  at  least  to  a  certain  extent,  by  fill- 
ing the  cavity  between  the  enamel-organ  and  the  enamel  with 
cilloidin.  The  cavity  or  space  is  evidently  the  result  of  shrink- 
age of  the  delicate  myxomatous  tissue  in  the  enamel-organ.  A 
peculiar  asymmetry  is  often  met  with,  one  side  l^eing  very 
broad  and  the  other  very  narrow.  Peculiar  indentations,  also, 
are  often  seen  in  the  course  of  the  inner  epithelium.  Whether 
or  not  all  of  this  is  artiiicial,  and  due  to  shrinkage,  we  are  unable 
to  state,  but  it  is  certain  that  as  soon  as  the  enamel  begins  to 
appear  there  are  marked  differences  in  the  structure  of  the 
inner  epithelium.  At  the  bottom  of  the  enamel-organ,  corre- 
sponding to  the  future  neck  of  the  tooth,  the  inner  epithelium 
is  found  to  l)e  transformed  into  medullary  tissue,  and  the  edge 
between  the  inner  and  outer  epithelium  is  likewise  filled  with 
medullary  tissue.  Higher  up,  along  the  border  of  the  papilla, 
where  there   is    as   vet  no    enamel,   we  find  formations  that 


DEVELOPMEXT  OF  THE  EXAMEL.  171 

resemble  the  original  epithelia,  but  which  iu  this  condition  are 
termed  ameloblasts.  The  intermediate  layer,  in  connection 
with  the  ameloblasts  in  this  stage,  is  alwa^'s  markedly  devel- 
oped. Still  higher  up,  where  ready-formed  enamel  is  present, 
the  ameloblasts  are  much  less  regular,  and  we  observe  that 
they  again  split  up  into  medullary  corpuscles.  From  this  we 
draw  the  conclusion  that  the  original  inner  epithelium  is  trans- 
formed into  medullary  corpuscles,  which  give  rise  to  the  amelo- 
blasts, and  that  the  latter,  before  being  transformed  into  enamel, 
once  more  break  up  into  medullar}'  tissue. 

In  a  specimen  prepared  from  a  human  foetus  of  five  months, 
there  is  scarcely  a  trace  of  the  inner  epithelium  left :  we  see 
nothing  of  that  tissue  except  a  succession  of  small  glistening 
medullary  corpuscles,  which,  by  their  arrangement  in  rows, 
remind  us  of  their  origin  from  previous  epithelia.  This  tissue 
remains  plainly  visible  even  in  the  sixth  and  seventh  months  of 
foetal  life,  especially,  as  mentioned  above,  at  the  fold  correspond- 
ing to  the  edge  of  the  enamel-organ  in  the  region  of  the  future 
neck  of  the  tooth.  Higher  up,  the  medullary  corpuscles,  which 
previously  were  scattered,  once  more  assume  a  line-like  arrange- 
ment, and  gradually  take  the  shape  of  narrow  elongated  cor- 
puscles, not  always  distinctly  nucleated,  and  these  elongated 
bodies,  somewhat  resembling  the  original  columnar  epithelia, 
are  termed  ameloblasts.     (Fig.  109.) 

One  of  the  striking  features  in  this  process  of  transformation 
is  the  presence  of  a  layer  forming  the  outermost  portion  of  the 
enamel-organ  toward  the  papilla  (Fig.  109,  P).  This  layer, 
with  low  powers  of  the  microscope,  appears  to  be  made  up  of 
finely-granular  protoplasm  with  interspersed  granular  nuclei. 
Above  this,  marks  of  division  appear  in  the  protoplasmic  layer, 
and  the  marks  correspond  to  the  boundary  lines  of  the  rows  of 
the  glistening  medullary  corpuscles,  the  forerunners  of  the 
future  ameloblasts.  There  is  a  transitional  stage,  as  referred  to 
In  Fig.  109,  in  which  the  inner  portions  of  the  ameloblasts  are 
made  up  of  several  glistening  medullary  corpuscles,  whereas 
the  outermost  portion  is  finely  granular,  or  made  up  of  a  deli- 
cate reticulum.  The  ameloblasts  in  the  seventh  month  of  foetal 
life  are  distinctly-marked  formations,  and  are  present  only  on 
places  where  enamel  has  not  yet  been  formed.  They  are  in 
junction,  side  by  side,  from  the  region  of  the  neck  to  the  sum- 
mit of  the  crown.     They  are  composed  of  finely-granular  pro- 


172 


THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


toplasm,  Avitli  one  or  several  nuclei,  or  sometimes  without  any 
distinct  nucleus.  Their  general  form  is  columnar,  slightly 
broadened  toward  the  papilla.  Often,  however,  they  exhibit 
parallel  contours,  or  a  wedge-shape,  between  two  neighboring 


Fig.   109. 


Segment  near  the  Fold  of  the  Enamel-organ,  corresponding  to  the   Neck  of  the 
Future  Tooth  of  a  Human  Fcetus  of  the  Seventh  Month. 

PP,  papilla;  5*,  stellate  reticulum  in  an  early  stage  of  development ;  31,  medullary  corpuscles 
in  a  nearly  uniform  distribution,  becoming  elongated  higher  up,  and  arranged  in  rows;  A, 
ameloblasts  at  an  early  stage  of  formation,  composed  of  medullary  corpuscles  ;  P,  protoplasmic 
bodies  producing  the  outermost  portion  of  the  enamel-organ.    Magnified  1200  diameters. 


funnel-shaped  ameloblasts  (see  Fig.  106,  A).  All  ameloblasts 
are  interconnected  by  delicate  conical  threads  traversing  the 
light  interstices  between  them.     Their  layer  is  easily  distin- 


DEVELOPMENT    OF    THE    EXAMEL 


173 


guislied  from  the  stellate  retic-uluni  hy  the  intermediate  layer, 
which  is  composed  of  spindles  and  libers.  From  their  Ijases 
delicate  short  ofishoots  often  emanate  (Tomes's  processes),  which, 
however,  do  not  exhibit  any  regnlar  arrangement.  Where  the 
layer  of  ameloblasts  is  detached  from  the  surface  of  the  papilla, 
similar  short  processes  emanate  from  the  surface  of  the  latter, 
and  it  is  obvious  that  all  these  fine  oftshoots  serve  for  an  inter- 
connection between  the  ameloblasts  and  the  medullary  cor- 
puscles of  the  papilla. 

Fig.  110. 


EiRST-EOEMED   EXAMEL   OF   A    HuMAX    FcETUS    OF    SiX   Mo.XTHS. 

B,  dentine  bounded  toward  the  enamel  by  bay-like  excavations ;  E,  enamel  composed  of 
prismatic  pieces  ;  -1,  rows  of  medullary  corpuscles  sprung  from  previous  ameloblasts.  Magni- 
fied 1000  diameters. 


Still  nearer  the  summit  of  the  crown  the  ameloblasts  once 
more  lose  their  character,  and  once  jiiore  break  up  into  medul- 
lary corpuscles,  more  or  less  retaining  their  row-like  arrange- 
ment. We  observe  that  the  medullary  corpuscles  which  lie 
nearest  to  the  already-formed  dentine  are  finely  granular, 
whereas  the  rows  some  distance  above  are  coarsely  granular  or 
homogeneous.  These  finely-granular  medullary  corpuscles  are 
at  last  infiltrated  with  lime-salts,  and  thus  is  produced  the 
enamel  proper.     (Fig.  110.) 


174  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

The  first  trace  of  enamel,  as  is  well  known,  appears  about 
the  sixth  month  of  intra-uterine  life,  at  a  period  when  a  certain 
amount  of  dentine  has  already  been  formed.  The  outer  sur- 
face of  the  dentine  exhibits  bay-like  excavations,  in  which  we 
often  observe  a  flat  layer  of  a  finely-granular  protoplasm,  analo- 
gous to  that  found  in  the  teeth  of  adults.  Above  this  layer  we 
see  prismatic  pieces  of  calcified  basis-substance  irregularly  dis- 
tributed, since  the  enamel-prisms,  as  a  rule,  do  ,not  reach  the 
surface  of  the  dentine,  luit  are  replaced  by  a  homogeneous 
(Tomes's  granular)  layer.  Yet  above  this  the  enamel-prisms  are 
easily  recognizal)le,  and  appear  to  be  composed  of  more  or  less 
regular  square  pieces.  We  can  see  a  deposition  of  lime-salts 
along  the  borders  of  the  prisms,  while  their  central  parts  often 
exhibit  one  large  nucleus,  or  several  coarse  granules.  The 
interstices  between  the  rows  of  these  square  pieces  frequently 
exhibit  delicate  fibrillse,  the  enamel-fibers,  which  are  in  connec- 
tion with  broader  protoplasmic  tracts,  lying  in  the  boundary 
between  the  enamel  and  the  dentine.  These  enamel-fibers  send 
branches  through  the  transverse  interstices  of  the  square  pieces. 
Everywhere  delicate  offshoots  are  seen,  indicating  that  the  living 
matter  of  the  previous  medullary  corpuscles  is  preserved,  even 
after  their  infiltration  with  lime-salts. 

In  the  eighth  and  ninth  months  of  foetal  life,  both  the  enamel 
and  the  dentine  form  solid  caps,  corresponding  to  the  summit 
of  the  crown  of  the  tooth,  and  the  one  is  superimposed  upon 
the  other.  In  decalcified  specimens  of  these  tissues,  when  they 
have  been  stained  with  carmin  or  chloride  of  gold,  we  observe 
a  striking  analogy  in  the  structure  of  the  enamel  to  that  of  the 
dentine.  With  a  magnifying  power  of  500  diameters,  it  is  difil- 
cult  to  difl:erentiate  between  dentine  and  enamel.  The  fibers 
in  the  canaliculi  of  the  dentine  closely  resemble  those  of  the 
interstices  between  the  enamel-rods.  Even  the  highest  powers 
of  the  microscope  exhibit  a  close  resemblance  of  both  tissues, 
more  especially  after  the  Jime-salts  have  been  completely  re- 
moved by  means  of  reagents. 

Let  us  now  ask  the  question,  What  is  the  ultimate  fate  of 
the  epithelial  cord  of  the  enamel-organ? 

In  the  earliest  stage  of  its  development  we  meet  Avith  num- 
erous lateral  offshoots  and  sprouts,  which,  preceding  their 
ultimate  disappearance,  are  visible  in  the  shape  of  medullary 
corpuscles.     The   destiny  of  the  cord  is  obviously  to  produce 


DEVELOPMENT  or  THE  ENAMEL.  175 

the  enamel-organ  for  the  formation  of  the  enameL  This  pro- 
cess is  accomplidied  with  the  lifth  month  of  intra-nterine  Kfe. 
In  the  latter  part  of  the  fourth,  and  in  the  lifth  month,  the 
orio:inal  epithelial  cord  undergoes  peculiar  changes,  which  have 
attracted  the  attention  of  many  previous  observers.  The  main 
change  consists  in  the  breaking  up  of  the  epithelial  cord  into 
innumerable  clusters  of  a  more  or  less  markedly  epithelial 
structure,  between  which  fibrous  connective  tissue  has  appeared, 
completely  isolating  the  clusters.  Changes  of  this  description 
are  best  seen  in  horizontal  sections  of  the  jaws.     (See  Fig.  107.) 

With  low  powers  of  the  microscope,  we  observe  a  large 
number  of  clusters  which  are  distinctly  marked  in  specimens 
preserved  in  chromic-acid  solution.  They  have  a  brownish 
color,  and  may  be  either  sharply  outlined  or  more  or  less 
blended  with  the  adjacent  connective  tissue.  Many  of  these 
clusters  hold  concentrically-arranged  epithelial  nests,  and, 
judged  by  their  size  and  shape,  they  must  have  originated  from 
a  very  active  new  gro"\^i:h  of  epithelium,  which  is  indicated 
also  by  a  number  of  buds  sprouting  from  the  original  clusters. 
The  buds  have  been  j)^^shed  apart  by  librous  connective 
tissue,  since  many  of  them  appear  entirely  isolated,  and  as  if 
imbedded  in  the  fibrous  connective  tissue.  Higher  powers  of 
the  microscope  reveal  the  fact  that  the  process  of  dissolution  of 
the  original  epithelial  cord  is  identical  with  that  of  the  disso- 
lution of  the  external  epithelium,  the  only  difference  being 
that  in  the  latter  process  numerous  newly-formed  blood-vessels 
participate,  whereas  in  the  breaking  up  of  the  epithelial  cord 
the  new  formation  of  blood-corpuscles  and  blood-vessels  is  not 
very  conspicuous.     (See  Fig.  111.) 

The  smallest  isolated  clusters,  still  recognizable  by  their 
brownish  color,  only  show  traces  of  a  division  into  epithelia 
through  an  intervening  cement^substance.  Most  of  them  rep- 
resent protoplasmic  masses,  with  nuclei  of  varying  size,  inter- 
spersed at  more  or  less  regular  intervals.  Such  clusters  are 
often  found  surrounded  by  an  almost  homogeneous  layer  of  a 
so-called  basement-membrane.  In  the  next  stage,  the  cluster 
splits  up  into  medullary  corpuscles  at  its  periphery,  whereby 
its  size  is  considerably  diminished,  and  the  basement-membrane 
lost.  Ultimately  the  multinuclear  protoplasmic  mass,  or  the 
medullary  corpuscles,  split  up  into  delicate  spindles,  which 
become  infiltrated  with  basis-substance,  thereby  assuming  the 


176 


THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH, 


cliaraoteristie  features  of  fil)rous  connective  tissue.  Some- 
times we  meet  with  single  brownish  corpuscles  imbedded  in 
fibrous  connective  tissue,  and  in  size  surpassing  the  nuclei  of 
the  latter.  Such  formations  are  possibly  the  last  remnants  of 
previous  epithelia,  that  have  escaped  transformation  into  con- 
nective tissue. 

The  ultimate  fate,  then,  of  the  epithelial  cord  of  the  enamel- 
Fro,  in. 


Dissolution  of  the  Epithelial  Coed  of  Examel-Organ  of  a  Human  Fcetus  Five 
Months  Old.  Horizontal  Section. 
C,  capillary  blood-vessel  holding  red  blood-corpuscles;  B,  B,  multinuclear  protoplasmic 
masses  arisen  from  the  original  epithelial  buds;  R,  remnants  of  previous  epithelia  partly 
transformed  into  medullarj'  corpuscles  ;  E.  single  protoplasmic  body,  probably  epithelium  ;  M, 
medullary  corpuscles  in  transition  to  fibrous  connective  tissue.    Magnified  800  diameters. 

organ  is  the  same  as  that  of  the  external  epithelium,  the  cord 
being  partly  transformed  into  connective  tissue.  The  further 
the  development  of  the  enamel  and  the  enamel-organ  proceeds, 
the  less  is  visible  of  the  original  epithelial  cord,  although  small 
epithelial  clusters  may  be  recognizable  even  in  the  sixth  and 
seventh  months  of  fcptal  life. 


DEVELOPMENT    OF    THE    EXA.MEL. 


177 


We  have  already  alluded  to  tlie  possibility  tliat  the  epithelium 
present  between  the  outer  surface  and  the  enamel  serves  as 
stored-up  material  for  the  increase  of  the  enamel,  a  possibility 
assumable  since  at  the  time  of  birth  this  tissue  has  by  no  means 
attained  the  full  thickness  which  we  observe  at  the  time  of  the 

Fig.  112. 


r 


■vCtr.m 


Tooth  of  a  Hl'man  Fcetcs  Seven"  axd  a  Half  Months  Old.    Vertical  Sectiox. 
P,  papilla :  B,  dentine :   E,  enamel ;    IE,  internal  epithelium ;  EO,   enamel-organ  ■  EE 
external  epithelium:    R,  remnants  of  epithelial  cord:   EN,  epithelial  nest:    EP,  pit  filled 
loosely  with  flat  epithelia :  RM,  rete  mueosum ;  Ep,  horny  layer  of  the  oral  mucosa.    Magnified 
50  diameters. 


eruption  of  the  tooth,  and  since,  also,  on  that  part  of  the  surface 
corresponding  to  the  summit  of  the  enamel  there  is  no  proper 
enamel-organ  left  for  the  further  growth  of  enamel-tissue. 
The  epithelial  cord  does  not,  however,  completely  disappear 


178  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

toward  the  end  of  intra-nterine  life.  Near  the  surface  of  the 
oral  mucosa  we  ofteu  meet  with  comparatively  large  spaces 
filled  with  loosely-arranged  flat  epithelia  of  the  character  of 
epidermal  scales,  as  illustrated  in  Fig.  112. 

Thus  far  we  have  heen  unable  to  trace  the  connection  of 
such  a  large  pit  with  the  rete  mucosum,  or  surface  of  the  oral 
epithelium.  But  there  can  he  no  doubt  as  to  the  origin  of  the 
pits.  They  must  have  arisen  from  the  original  epithelial  cord, 
since  the  epithelial  cord  of  the  permanent  tooth  may  be  traced 
from  their  periphery.  The  cord  in  our  specimen  is  broadened 
at  its  distal  end  and  surrounded  by  a  small  papilla  correspond- 
ing in  every  respect  to  the  developing  temporary  tooth  in  an 
embryo  of  about  three  and  a  half  months.  The  epithelia  filling 
the  pit  are  arranged  loosely,  similar  to  those  of  the  horny 
layer  of  the  oral  mucosa,  and  many  of  them  hold  glistening 
granules  of  what  possibly  is  eleidin.  The  boundary  of  the 
pit  is  made  up  of  a  single  row  of  cuboidal  epithelia,  which  in 
some  places  may  produce  stratified  hills  and  protrusions.  The 
pit  corresponds  to  the  summit  of  the  temporary  tooth,  and  its 
destiny  seems  to  be  to  prearrange  the  route  for  its  eruption. 
Between  the  lower  periphery  of  the  pit  and  the  upper  bound- 
ary of  the  enamel-organ,  or  rather  its  external  epithelium,  the 
connective  tissue  is  loose  and  approaches  the  myxomatous 
structure,  containing  very  small  groups  of  epithelium  or  medul- 
lary corpuscles  sprung  therefrom.  Such  clusters  are  especially 
conspicuous  in  the  space  between  the  epithelial  cord  of  the 
permanent  tooth  and  the  external  epithelium  of  the  enamel- 
organ,  where  a  large  number  of  capillary  blood-vessels  is  also 
visible. 

Among  the  different  animals  in  whose  jaws  we  have  examined 
the  process  of  formation  of  the  enamel,  we  may  mention  the 
following : 

Kittens,  at  the  time  of  birth,  show  all  stages  of  the  formation 
of  teeth,  and  especially  the  breaking  up  of  the  inner  epi- 
thelium into  medullary,  and  afterward  into  myxomatous,  tissue, 
which  is  easily  traceable.  All  the  details,  however,  correspond 
to  those  observed  in  human  beings. 

In  a  newly-born  pup  the  formation  of  enamel  was  found  to 
be,  in  all  essential  points,  identical  with  its  formation  in  man. 

The  foetus  of  a  pig  affords  an  excellent  example  for  the  study 
of  the  formation  of  ameloblasts   from  medullary  corpuscles. 


DEVELOPMENT    OF    THE    EXAMEL. 


179 


(Fig.  113.)  The  ameloblasts  are  arranged  with  great  regularity, 
l)eing  alternately  wedge-shaped  in  opposite  directions.  Their 
reticulum  is  very  wide,  and  the  horizontal  threads  traversing 
the  interstices  are  quite  plain.  From  their  bases  arise  a  varying 
number  of  offshoots,  directed  toward  a  peculiar  tissue  which 
occupies  the  space  between  the  ameloblasts  and  the  already- 
formed  dentine.  This  tissue  appears  granular  with  low  powers 
of  the  microscope.      High  powers,  however,  plainly  reveal  a 


Fig.  113. 


A.MELOBL.A.STS  OP  A  Pig'S    FffiTUS,  ABOUT   TeX   CeXTIMETERS  LoxG,  BEFORK  THE  FORMATION 

OF   EXAMEL. 

M,  Myxomatous  enamel-organ  ;  A,  A,  rows  of  ameloblasts  of  a  markedly  reticular  structure ; 
G,  granular  layer  between  the  dentine  and  the  ameloblasts.    Magnified  1200  diameters. 

reticular  structure,  traversed  by  delicate  fibrillae  in  connection 
with  the  reticulum.  The  presence  of  nuclei  in  this  tissue  indi- 
cates its  origin  from  medullary  corpuscles. 

The  foetus  of  a  lamb,  about  ten  centimeters  long,  shows  a 
large  layer  of  ameloblasts.  (Fig.  114.)  In  places  where  the 
ameloblasts  lie  close  to  the  dentine,  no  filDrill^e  are  seen,  but 
where  the  layer  of  ameloblasts  is  detached,  a  large  number  of 
fibrillae  appear,  e^-idently  belonging  to  the  dentine.  This  is  less 
calcified  and  takes  up  a  deep  carmin  stain,  contrary  to  the 
fully-calcified  central  portion  of  the  dentine,  that  usually  re- 


180 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


mains  unstained.  Here  is  wedged  in  between  the  dentine  and 
the  ameloblasts  a  hirer  found  only  as  bek^nging  to  the  sheep. 
The  amelobhists  break  up  into  medullary  corpuscles  before 
forming  enamel,  in  the  same  manner  as  in  human  beings  and 
other  animals  that  we  have  examined. 


Sectiox  of  a  Tooth  of  4.  Sheep's  Fcftus,  4.B0bT  Ten  Centimeters  Long. 


D,  dentine  in  transverse  section  ;  F,  fibers  drawn  out  from  the  non-calcified  portion  of  the- 
dentine;  A,  layer  of  ameloblasts  partly  in  connection  with  the  dentine.  Magnified  1200  diameters- 

Valuable  researches  in  the  study  of  the  development  of  the 
enamel  have  been  published  by  Frank  Abbott,*  as  follows : 

*  "Growth  of  Enamel."     Dental  Cosmos,  1889. 


DEVELOPMENT    OF    THE    EXAMEL.  181 

"  A.  Kolliker,  in  liis  '  Handbook  of  Histology  of  Man'  (1852), 
speaks  of  development  of  enamel  in  the  following  terms : 
*  The  development  of  the  dental  substances  has  always  been 
considered  a  rather  difficult  topic.  The  relations  are  the  simplest 
in  the  enamel,  where  not  the  slightest  doubt  prevails  that  the 
enamel-cells,  bj  a  complete  calcification,  become  transformed 
into  enamel-fibers  (enamel-rods).  As  soon  as  a  small  portion 
of  the  cells,  without  am'  preliminary  deposition  of  lime-parti- 
cles, is  being  ossified,  we  recognize  a  small  lamella  of  enamel 
over  the  somewhat  larger  dentine  cap,  which  has  also  recently 
originated.  The  deposition  of  lime  proceeds  in  the  cells  from 
within  outward  till  they  have  at  last  been  transformed  into 
enamel-fibers  and  simultaneously  transgress  on  new  cells,  by 
which  means  the  layer  of  enamel  is  broadened.  AVhile  this  is 
going  on,  the  enamel-membrane  has  not  disappeared  at  the 
place  where  the  ossification  has  started.  On  the  contrary,  we 
find  this  membrane  always  of  the  same  In-eadth  so  long  as  the 
deposition  of  the  enamel  lasts,  which  proves  that  the  ossified 
portion  of  the  membrane  is  continuously  being  replaced  by  an 
additional  mass.  Apparently  this  is  done,  not  l;)y  the  produc- 
tion of  new  cells,  but  by  a  continual  outgrowth  of  the  original 
ones.  The  enamel-organ  (stellate  reticulum)  is  certainly  of 
great  importance  in  the  building  up  of  enamel,  and  owing  to 
its  richness  in  albumen  and  a  gelatinous  mass  in  its  meshes  is,  so 
to  speak,  a  pantry  from  which  the  enamel-membrane  derives 
the  material  for  its  growth,  being  at  some  distance  from  the 
blood-vessels.  In  fact,  we  see  this  spongy  tissue  losing  in  its 
bulk  during  the  development  of  enamel,  and  finally  disappear- 
ing when  the  formation  of  enamel  is  completed.' 

''  I  will  here  add  that  to  Kolliker  the  enamel-membrane  means 
a  layer  of  epithelia.  He  describes  the  enamel-organ  as  being 
made  up  of  anastomosing  star-shaped  cells,  or  a  reticular  con- 
nective tissue,  which  in  its  meshes  contains  a  large  amount  of 
albumen  and  a  liquid  rich  in  mucus.  The  same  author,  in  his 
work  on  the  '  Historj'  of  Development  of  Man  and  Higher 
Animals,'  in  1879,  claims  that  the  stellate  reticulum  of  the 
enamel-organ  in  appearance  is  identical  ^^ith  connective  tissue, 
but  is  really  nothing  but  a  peculiarly  transformed  epithelium. 
Kolliker,  therefore,  in  1852,  held  an  opinion  that  we  consider 
to-day  the  correct  one,  which  he  very  materially  modified, 
almost  to  the  point  of  al)andonment  altogether,  years  later. 


182  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

This  author  was  the  first  to  announce  that  the  theory  of  exehi- 
siveness  is  not  tenable,  in  the  process  of  development  from  the 
three  original  embryonal  layers,  the  '  ectoderm,'  the  '  meso- 
derm,' and  the  '  entoderm,'  or,  using  Balfour's  terminology, 
the  '  epiblast,'  the  '  mesoblast,'  and  the  '  hypoblast' ;  and  still 
he  narrows  his  views  to  an  almost  incredible  degree,  in  the 
chapter  upon  development  of  enamel. 

''John  Tomes,  in  his  'Dental  Physiology  and  Surgery'  (Lon- 
don, 1848;  Philadelphia,  1853),  gives  wonderfully  accurate 
drawings  of  what  he  calls  enamel-pulp,  or  columnar  tissue,  now 
known  as  ameloblasts.  On  page  102  he  explains  the  develop- 
ment of  enamel-rods  or  fibers  in  the  following  words :  '  The 
cells  being  formed  in  lines,  eventuall}"  become  confluent;  the 
points  of  union  being  somethiies  transverse,  and  at  other  times 
oblique,  At  this  stage  the  earthy  elements  are  received,  and 
the  lines  of  union  between  the  component  cells  of  the  fibers 
become  less  distinct,  and  are  eventually  lost,  leaving  a  continu- 
ous fiber.  The  nuclei,  from  the  first  very  small,  are  altogether 
lost  in  the  formation  of  the  fibers,  or  exist  as  very  fine  tubes 
passing  through  the  length  of  each.' 

"  On  page  104  we  read :.  '  To  the  best  of  my  belief  the  trans- 
verse striae  are  due  to  the  alternate  dilatation  and  contraction 
of  the  fibers, — each  dilatation  corresponding  to  the  center  of  a 
formative  cell,  and  each  contraction  to  the  junction  of  two 
cells.' 

"From  these  cpiotations  it  becomes  evident  that  John  Tomes 
was  a  most  careful  observer.  Even  at  that  early  date,  with  the 
limited  powers  of  his  microscope,  he  conceived  the  full  truth 
when  he  stated  '  that  each  enamel-rod  is  the  result  of  a  juxta- 
position of  formative  cells,  between  which  are  left  the  stride.' 
He  considers  the  formative  cells  as  the  recipients  of  the  cal- 
careous matter  in  exactly  the  same  way  as  we  see  it  to-day. 

"  F.  "Waldeyer,  in  his  '  Handbook  of  Histology,'  edited  by 
Strieker,  in  Leipzig,  JL869,  page  347,  describes  the  formation  of 
enamel  in  the  following  manner :  '  The  formation  of  enamel  is 
done  exclusively  by  the  enamel-epithelium,  since  the  enamel- 
prisms  are  the  result  of  a  direct  calcification  of  its  long  cylin- 
drical cells.  The  boundary  of  petrifaction  on  the  cells  is  by  no 
means  linear,  but  extends  downward  to  an  irregular  depth, — a 
fact  which  likewise  is  not  in  favor-  of  the  view  that  a  secretion 
of  the  enamel-cells  is  being  calcified.     After  treatment  of  young 


DEVELOPMENT  OF  THE  ENAMEL.  183 

enamel  with  dilute  acids,  the  enamel-prisms  slightly  swell  and 
resume  entirely  the  form  of  the  previous  cylindrical  cells. 
The  disappearance  of  the  nuclei,  in  the  process  of  the  calcifica- 
tion of  the  cells,  is  of  so  common  occurrence  that  their  absence 
in  the  enamel  cannot  cause  any  wonder.  Enamel,  therefore,  is 
to  be  considered  as  the  petrified  dental  epithelium.' 

"  This  author  explains  the  formation  of  the  stellate  reticulum 
by  a  transformation  of  the  epithelia,  and  considers  its  gelatin 
of  a  merely  mechanical  importance,  since  it  keeps  an  open 
space  for  the  growing  tooth. 

"  John  and  Charles  S.  Tomes,  in  their  '  System  of  Dental  Sur- 
gery' (London,  1873,  page  253)  say,  '  The  conclusions  respect- 
ing the  development  of  enamel  which  are  most  in  accordance 
with  appearances  observed  are  these :  The  columns  of  the 
enamel-organ  (enamel-cells,  internal  epithelium  of  the  enamel- 
organ)  are  subservient  to  the  development  of  the  enamel-prisms, 
into  which  they  by  calcification  become  actually  converted. 
This  conversion  goes  on  in  the  folloA^dng  method :  The  proxi- 
mal end  of  the  cell  undergoes  some  chemical  change  prepara- 
tory to  calcification,  and  is  subsequently  calcified ;  but  this  cal- 
cification does  not  go  on  uniformly  throughout  its  whole  thick- 
ness, but  proceeds  from  its  periphery  toward  its  interior,  the 
central  portion  of  the  cell  thus  being  calcified  later  than  the 
external  portion,  which  lies  at  the  same  level.  At  the  same 
time  that  calcification  is  proceeding  inward,  in  each  individual 
cell,  it  has  united  the  contiguous  cells  to  each  other.  The  cal- 
cification of  the  central  portions  of  the  enamel-fibers  does  not 
keep  pace  with  that  of  their  exteriors,  nor  even  in  fully-com- 
pleted enamel  does  it  attain  to  precisely  the  same  characters. 
In  the  progress  of  calcification  the  nuclei  of  the  enamel-cells 
disappear,  and  it  is  probable,  as  is  believed  by  Waldeyer,  that 
the  internal  epithelium  of  the  enamel  is  reunited  by  the  cells  of 
the  stratum  intermedium  as  it  becomes  itself  used  up  by  ad- 
vancing calcification,  converting  it  into  enamel-fibers.' 

"  These  authors  give  credit  to  KoUiker  as  the  originator  of  the 
idea  that  the  enamel-cells  do  not  undergo  direct  conversion  into 
enamel-fibers,  but  that  the  enamel  is,  as  it  were,  shot  out  from 
their  ends, — that  is,  it  is  a  secretion  from  them,  not  a  deposition 
of  lime-salts  into  their  own  substance.  Our  quotations  from 
Kolliker's  original  German- work,  issued  in  Leipzig  in  1852, 
plainly  show  that  he  at  that  time  believed  fully  in  the  conver- 


184  THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

sion  tlieory.  Since  the  Tomeses  quote  from  the  fitth  German 
edition  of  Kohiker's  histology,  issued  in  1867,  it  is  obvious  that 
he  has  changed  his  views,  much,  in  my  judgment,  to  his  own 
disadvantage. 

"  The  views  announced  b}'  C.  Heitzmann  and  C.  F.  W.  Bo- 
decker  are  in  harmony  with  my  own  observations,  and  fur- 
nish the  foundation  of  what  I  have  to  add,  in  the  way  of  a 
more  comprehensive  idea  of  the  building  process  of  enamel, 
than  has  heretofore  been  advanced. 

"Fig.  115  gives  an  illustration  of  the  views  just  alluded  to. 
The  figure,  it  must  be  emphasized,  is  not  diagrammatic,  but 
copied  with  the  utmost  care  from  a  specimen  of  a  human  foetus 
six  months  old,  the  period  at  which  enamel  begins  to  appear. 
The  diiferent  layers,  it  will  be  observed,  appear  separated  from 
one  another.  This  is  usually  the  case  even  in  the  most  care- 
fully prepared  specimens,  o'^^'ing  to  slight  mechanical  injury  in 
cutting,  and  to  shrinkage  of  the  soft  parts ;  the  relations,  how- 
ever, are  absolutely  correct  in  this  drawing. 

"After  the  epithelial  peg  has  grown  into  the  depth  of  connec- 
tive tissue  of  the  oral  mucosa,  in  the  twelfth  week  of  embry- 
onal development,  the  distal  end  of  this  peg  becomes  club- 
shaped,  and  then  appears  the  first  trace  of  medullary  tissue, 
which  two  weeks  later  plainly  shows  the  stellate  reticulum. 
The  club  at  this  period  assumes  a  cup-shape,  Avhose  concave 
surface  is  lined  by  the  internal  epithelium,  while  the  outer  sur- 
face is  made  up  of  the  so-called  external  epithelium,  which  is 
in  uninterrupted  continuity  with  the  internal  epithelium  at  the 
most  prominent  l)order  of  the  cup.  If  we  examine  the  lower 
edge  of  the  cup  of  the  enamel-organ  at  al)Out  the  sixteenth 
week  of  embryonal  life,  we  observe  a  peculiar  change  in  the 
columnar  bodies  of  the  internal  epithelium,  which  consists  in 
the  appearance,  in  a  more  or  less  row-like  arrangement,  of 
highly-glistening  globular  bodies,  replacing  the  previous  col- 
umnar epithelia.  These  bodies  are  either  solid  or  slightly 
vacuoled,  and  are  formations  of  living  matter  such  as  we  are 
accustomed  to  look  upon  as  medullary,  embryonal,  or  indifter- 
ent  corpuscles  in  their  earliest  stage  of  appearance.  Obviously 
these  glistening  globules  have  originated  from  the  reticulum  of 
living  matter  of  the  columnar  epithelia  themselves.  We  feel 
justified  in  this  conclusion  from  the  fact  that  we  can  trace,  step 
by  step,  the  growth  of  these  glistening  granules  up  to  the  for- 


DEVELOPMENT  OF  THE  ENAMEL.  185 

matiou  of  o-Usteiiiug  lumps,  such  as  we  have  termed  medullary 
corpuselesr    The  niore  the  cup  of  the  euamel-orgau  is  eularged, 

Fig.  115. 


^t^^il^'r 


Tooth  of  Humax  Fcetcs,  Six  Moxths. 
P,  papilla;  D^,  non-calcified  dentine:  X>2,  calcified  dentine:  E.  enamel:  ^,  row  of  amelo- 
■blasts;  3/,  medullary  corpuscles  at  the  peripheral  portion  of  ameloblasts;  <i.  globular  cor- 
puscles from  which  ameloblasts  develop:  iJi;,  buds  of  external  epithelium:  i^,  follicle,  made 
up  of  fibrous  connective  tissue.    Magnified  lUO  diameters. 

the  more  couspicuous  becomes  the  transmutation  of  the  pre- 
vious internal   epithelium  into   glistening  lumps:  so  much  so 


186  THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

that  toward  the  end  of  the  tifth  niontli  of  fcetal  life  the  original 
eokimnar  epithelium  at  the  concave  portion  of  the  cup  has 
entirely  disappeared.  In  its  stead  hegin  to  show,  iirst  at  the 
deeper  portion  of  the  cup,  and  closely  resembling  columnar 
epithelia,  other  bodies,  now  known  as  ameloblasts,  or  enamel- 
formers. 

"  From  this  description  it  seems  evident  that  all  previous  ob- 
servers— be  it  said  with  due  respect  to  their  judgment — have 
been  in  error  in  the  assumj^tion  that  the  columnar  epithelia  of 
the  internal  wall  of  the  cup  were  identical  with  the  ameloblasts. 
All  these  observers  have  overlooked  the  intermediate  stage  of 
the  glistening  medullary  lumps.  In  Fig.  116  these  lumps  are 
marked  G.  They  are  traceable  down  to  the  neck  of  the  papilla, 
therefrom  to  the  point  of  recurvation  of  the  previous  internal 
into  the  previous  external  epithelium.  The  lumps,  I  wish  to 
repeat,  are  extremely  glossy,  with  a  high  degree  of  refraction. 
They  are  arranged,  at  first  irregularly,  in  a  layer  of  consider- 
able breadth,  and  higher  up  in  rows,  and  by  their  coalescence 
and  prolongation  give  rise  to  small  columns,  the  ameloblasts. 
These  are  seen  up  to  the  end  of  the  fifth  month  of  foetal  devel- 
opment at  the  deepest  concavity  of  the  cup  and  its  lateral  walls 
down  to  varying  depths,  and  closely  attached  to  the  now-form- 
ing dentinal  cap.  The  odontoblasts  grow  smaller  toward  the 
thin  extremity  of  the  dentinal  cap,  and  below  its  end  they 
appear  as  blunt  and  short  columns;  while,  close  above,  the 
ameloblasts  make  their  appearance,  being  traceable  all  around 
the  outer  periphery  of  the  dentinal  cap. 

"  In  the  sixth  month  of  fcetal  life,  as  is  well  known,  the  enamel- 
cap  begins  to  show ;  first  at  the  summit  of  the  dentinal  cap,, 
where  it  gains  its  greatest  breadth,  gradually  becoming  thinner 
toward  the  sloping  sides,  and,  as  a  whole,  a  trifle  thinner  and 
shorter  than  the  dentinal  cap. 

"  If  we  now  examine  the  ameloljlasts  close  above  the  already- 
formed  enamel,  we  shall  observe  finely-granular  bodies,  arranged 
in  a  row,  between  the  enamel  and  ameloblasts.  These  are  best 
seen  in  specimens  where, the  hardening  and  cutting  procedures 
have  not  caused  a  detachment  of  the  soft  tissues  from  the  hard^ 
— i.e.,  the  enamel-organ  from  the  calcified  enamel.  It  is  seldom 
that  this  is  accomplished;  but  a  few  of  such  perfect  specimens 
are  in  Boclecker's  collection,  which  by  his  kind  permission  I 
have  used  for  my  studies  and  these  drawings.     Even  though  a 


DEVELOPMENT  OF  THE  EXAMEL.  187 

slight  detacliment  has  occurred,  the  enamel-organ  still  remains 
intact,  and  the  finely-granular  corpuscles  at  the  proximal  ends 
of  the  ameloblasts  remain  visible. 

"  What  are  these  finely-granular  bodies  ?  Heitzmann  and 
Bodecker  claim  that  they  are  medullary  corpuscles,  holding 
small  and  indistinct  or  no  nuclei,  and  only  a  very  small  amount 
of  living  matter,  which  accounts  tor  their  finely-granular 
appearance  with  low  powers  of  the  microscope.  They  further 
claim  that  these  corpuscles,  or  the  liquids  contained  in  their  re- 
ticvilum,  become  solidified  into  basis-substance,  and  immediately 
infiltrated  with  lime-salts.  They  claim  also  that  the  enamel- 
rods  are  built  up  of  rows  of  such  calcified  or  '  petrified' 
medullary  corpuscles,  the  successive  arrangement  of  which  into 
rows  causes  the  more  or  less  regular  appearance  of  the  trans- 
verse strii3e  of  Retzius ;  whereas,  between  the  rows,  longitudinal 
interstices  will  remain,  filled,  perhaps,  with  a  small  amount  of 
cement-substance,  differing  in  its  chemical  constitution  from 
the  basis-substance  of  the  rods  proper,  and  in  its  interior  hold- 
ing extremely  delicate  fibrillee  (Bodecker's  enamel-fibers)  which 
branch  into  the  transverse  strise.  Being  satisfied  that  the  views 
of  these  gentlemen  are  correct,  I  will  simply  add  a  new  feature, 
to  make  those  views  more  symmetrical, — and,  as  it  occurs  to 
me,  it  is  a  feature  of  considerable  importance, — viz,  the  changes 
that  take  place  in  the  ameloblasts  during  the  process  of  the 
formation  of  enamel.     (Fig.  116.) 

"  The  ameloblasts,  as  just  stated,  split  up  into  rows  of  finely- 
granular  medullary  corpuscles,  and  consequently  are  reduced 
considerably  in  their  size.  In  fact,  it  is  difficult  to  find  fall- 
sized  ameloblasts  at  the  summit  of  the  enamel-cap,  where  the 
production  of  enamel  is  most  active,  the  same  as  it  is  impossi- 
ble to  find  full-sized  odontoblasts  at  the  summit  of  the  papilla, 
where  the  formation  of  dentine  is  most  active.  The  mutilated 
ameloblasts  in  this  situation  still  exhibit  nuclei,  although  their 
forms  are  odd, — mostly  cut  or  broken,  with  ofishoots  running 
upward  and  laterally  toward  the  stratum  intermedium.  At  the 
same  time,  peculiar  glistening,  homogeneous  lumps  and  irregu- 
lar wedge-shaped  nucleated  bodies  appear  between  the  ofishoots 
of  the  ameloblasts ;  not  as  regular,  however,  as  the  original 
medullary  corpuscles  were,  from  which  the  ameloblasts  origi- 
nally developed.  All  these  indifierent  bodies  must  have  arisen 
from  the  living  material  stored  up  in  the  stratum  intermedium, 


188 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


close  above  the  row  of  ameloblasts.  By  their  occasional  row- 
like arrangement  I  am  led  to  the  conclusion  that  thev  serve  for 
a  restitution  or  rebuilding  of  the  ameloblasts  (which  at  their  proxi- 
mal ends  have  split  up  into  enamel-formers),  and  thus  serve  to 
establish  a  continuity  of  the  ameloblasts,  and,  in  turn,  of  the 

Tig.   116. 


me //A      '^6 


First-Formed  Enamel  of  Humax  Fcetus,  Six  Moxths. 

D,  dentine  :  E,  enamel  toward  the  dentine,  made  up  of  irregular  calcified  fields,  toward  the 
periphery  of  prisms  with  transverse  interruptions :  M,  medullary  corpuscles,  finely  granular, 
from  which  the  enamel-prisms  are  formed:  ^,  ameloblasts.  toward  the  enamel  breaking  up 
into  medullary  corpuscles,  toward  the  periphery  rebuilt  by  such  corpuscles ;  A^,  irregular 
ameloblasts  torn  from  their  connection  with  enamel;  F,  fibrous  connective  tissue,  changing  to 
medullary  tissue.   Magnified  800  diameters. 


enamel-rods,  throughout  the  whole  thickness  of  the  enamel. 
In  a  previous  article  I  have  endeavored  to  show  that  odonto- 
blasts, being  split  up  at  their  distal  ends  into  medullarv  cor- 
puscles, enter  directly  into  the  formation  of  the  basis-substance 


DEVELOPMENT    OF    THE    EXAMEL,  ISO' 

of  dentine,  while  at  the  same  time,  continually  superadded  to 
the  proximal  ends  of  the  odontol)lasts,  are  medullary  corpuscles 
derived  from  the  living  matter  of  the  papilla.  Thus  the  con- 
tinuity of  the  odontoblasts  and  dentine  is  established,  stratifi- 
cation of  the  dentine  being  the  exception.  I  now  assert  a  simi- 
lar procedure  for  the  ameloblasts,  in  a  reverse  direction,  owing 
to  the  centrifugal  direction  of  enamel-growth.  The  ameloblasts 
being  br^oken  up  at  their  proximal  ends  into  medullary  corpuscles, 
which  are  directly  transfonned  into  blocks  of  enamel-rods,  are  super- 
added to  at  their  distal  or  peripheral  ends  by  medullary  rorpuscles 
derived  from  the  stratum  intermedium.  Xormal  enamel  is  non- 
stratified;  its  rods  or  prisms  run  a  wavy  course,  as  a  rule  un- 
interruptedly from  near  the  dentine  to  the  cuticular  (Nasmyth's) 
membrane. 

''  Xeither  the  structure  nor  the  development  of  this  tissue  is  to 
me  explicable  on  the  ground  of  the  cell  theory,  which  suggests 
that  each  cell  is  an  individual,  and  but  exceptionally  in  connec- 
tion with  its  neighbor.  To  us,  a  cell  is  a  lump  of  protoplasm,  in 
which  the  living  matter  is  stored  up  in  different  shapes.  The 
glistening  globules  of  small  size,  having  arisen  from  the  proto- 
plasm of  the  original  columnar  epithelia  of  the  enamel-organ, 
represent  a  juvenile  condition  of  living  matter  in  its  most  com- 
pact aggregation. 

"  The  medullary  corpuscles,  sprung  from  the  ameloblasts,  show 
only  a  delicate  reticulum  of  living  matter,  being  ready  for  im- 
mediate transformation  into  basis-substance  and  calcification. 
Between  these  extreme  stages  stand  the  ameloblasts,  with  their 
vesicular  nuclei,  and  a  markedly  heavy  reticulum  of  living 
matter  in  their  interior.  The  indiflerent  corpuscles,  serving  to 
supply  additions  to  the  ameloblasts,  exhibit  all  intermediate 
stages  between  small,  globular,  glossy  and  compact  globules  up 
to  distinctly-nucleated  protoplasmic  lumps.  "WTiatever  the  size 
and  shape  of  such  lumps  may  be,  they  are  invariably  connected 
with  one  another  by  means  of  delicate  offshoots,  which  vary 
greatly  in  thickness  and  in  their  course.  Each  ameloblast  sends 
offshoots  toward  the  dentine  in  great  numbers,  known  as  Tomes's 
processes.  They  also  run  upward  toward  the  intermediate 
layer,  and  laterally  for  the  immediate  union  of  neighboring 
ameloblasts.     (See  Fig.  117.) 

''  Broad  and  clumsy  offshoots,  such  as  depicted  by  Tomes  and 
Waldeyer,  are  visible  only  upon  torn  and  teased  ameloblasts.   Sa 


190 


THE    AXATOMY    AND    PATHOLOCtY    OF    THE    TEETH. 


long  as  these  bodies  are  in  situ,  the  offshoots  are  always  delicate, 
and  visible  with  higher  powers  of  the  microscope  only, — i.e., 
from  800  to  1000  diameters.  By  the  splitting  up  of  the  amelo- 
blasts  in  a  longitudinal  direction,  wedge-shaped  pieces  arise  be- 
tween funnel-shaped  or  square  bodies.  By  the  coalescence  of 
the  lateral  offshoots  in  a  longitudinal  direction,  delicate  librillse 
originate  between  the  ameloblasts,  known  as  Bodecker's  enamel- 
fibers. 

"When  the  formation  of  a  tissue  is  going  on,  we  conclude, 
from  the  great  variety  of  forms  of  the  protoplasmic  bodies,  that 

Fig.  117. 


^///P'<iM 


Ameloblasts  begixxixg  the  formation  of  Enamel  ;  from  Human  Fcetus,  Six  Months. 

JD,  border  of  newly-formed  dentine  ;  ^.-first  trace  of  forming  enamel ;  A,  row  of  ameloblasts ; 
3/1,  medullary  corpuscles  for  restitution  of  ameloblasts;  J/-,  medullary  corpuscles  just  previous 
to  their  infiltration  with  lime-salts :  F,  fibrous  connective  tissue,  the  so-called  intermediate 
laver.    Magnified  1000  diameters. 


there  is  not  for  a  moment  rest  either  in  the  growth  or  in  the  new 
formation  of  living  matter.  Thus  the  proximal  ends  of  the 
ameloblasts,  through  the  intermediate  stage  of  medullary  cor- 
puscles, are  metamorphosed  into  the  calcified  basis-substance  of 
the  enamel-rods.  The  distal  ends  exhibit  the  stages  through 
which  the  living  matter  passed  before  the  original  ameloblasts 
were  formed.  Still  the  question  remains  an  open  one,  w^hether 
or  not  ameloblasts  are  an  absolute  requirement  for  the  produc- 
tion of  enamel  after  the  formation  of  the  rods  has  once  begun. 
The  rows  of  globular  bodies  as  seen  in  Fig.  117,  M^,  strongly 


DEVELOPMENT    OF    THE    EXAMEL.  191 

favor  a  negative  answer  to  this  query.  Xothing  but  a  transmu- 
tation of  solid  globular  lumps  of  living  matter  into  delicately- 
reticulated  medullary  corpuscles  seems  to  be  required  for  the 
building  up  of  the  minute  blocks  of  enamel-rods,  without  the 
intermediate  stage  of  ameloblasts.  We  must  admit,  however, 
that,  to  symmetry  of  construction,  the  part  played  by  these 
bodies  seems  essential,  although  they  vary  greatly  in  size,  even 
in  the  same  tooth.  We  consider  ameloblasts  as  merely  provi- 
sional formations,  bv  no  means  stable  or  unchangeable.  This 
conclusion  is  the  same  as  that  we  reached  in  regard  to  the  sig- 
nificance of  odontoblasts. 

• "  Full  development  of  ameloblasts  into  oblong  or  conical 
bodies — each  containing  one  or  two  nuclei,  sharply  bordered 
by  a  delicate  cuticular  formation  toward  the  papilla,  and  dis- 
tinctly marked  by  the  intermediate  layer  toward  the  enamel- 
organ — is  never  seen  save  under  the  condition  of  temporary 
rest,  where  the  formation  of  enamel  has  not  as  yet  started. 
(See  Fig.  118.)  As  soon  as  the  first  trace  of  enamel  is  seen,  the 
ameloblasts  lose  their  regularity  by  being  split  up  toward  the 
dentine,  and  are  superadded  to  from  the  intermediate  layer. 

"  The  first-appearing  enamel  is  made  up  of  irregular  angular 
and  glistening  lumps,  greatly  varying  in  size.  (See  Figs.  116 
and  117.)  The  first  blocks  of  enamel-rods  show  compact  edges 
and  comparatively  thin  and  translucent  centers,  in  which  even 
traces  of  the  nuclei  of  the  medullary  corpuscles  are  to  be  seen. 
This  plainly  proves  the  correctness  of  the  assertion  of  Tomes, 
that  '  the  enamel-rods  are  calcified  from  the  periphery  toward 
the  center.'  The  irregularity  of  the  first-formed  calcified  blocks 
also  accounts  for  the  fact  that  fissures  and  breaks  are  of  such 
common  occurrence  in  specimens  of  enamel,  either  ground  or 
cut,  at  the  border  toward  the  dentine,  as  I  have  previously 
demonstrated  in  an  article  on  the  anomalies  of  enamel,  such 
anomalies  being  most  common  in  this  situation. 

"  We  now  return  to  the  enamel-organ,  of  which  it  is  known 
that  it  begins  to  show  at  the  end  of  the  third  month  of  intra- 
uterine life,  by  the  appearance  of  medullary  corpuscles  between 
the  internal  and  external  epithelium.  From  the  fourth  month 
to  the  seventh  or  eighth  the  beautiful  stellate  reticulum  known 
as  the  enamel-organ  comes  to  view.  Although  Huxley  and 
Kolliker  have  stated  (in  1850-1852)  that  this  is  connective  tissue, 
all  modern  writers,  including  Kolliker  himself,  insist  that  it  is 


192 


THE    AXATO-MY    A^'D    PATHOLOGY    OF    THE    TEETH. 


a  peculiarly-modified  epithelium.  I  contend  that  this  reticulum 
is  true  myxomatous  tissue,  and  the  stratum  intermedium  true 
filu'ous  connective  tissue.  The  first  microscopist  to  describe  and 
illustrate  tlte  intermediate  layer  was  John  Tomes,  in  1848,  in 
his  work  above  quoted.  This  credit  is  usually  given  to  Hanno- 
ver, whose  work  appeared  in  1856. 

'•As  to  the  significance  of  the  enamel-organ,  I  must  take  de- 
cided exception  to  the  views  of  most  modern  writers, — viz,  that 
it  serves  as  a  kind  of  protection  cushion,  or  to  preserve  an  open 
space  for  the  tooth  to  grow  into.  In  my  opinion,  the  ^^ew  first 
announced  by  Hertz  in  1866  is  the  correct  one, — i.e.,  that  '  the 

Fig.  118. 


A.MEI.OBLASTS    AT    ReST  ;    FROM    DEVELOPING    TOOTH    OF   HCMAX    FcETUS,    SiX    MOXTHS. 

A,  row  of  ameloblasts  :  /./,  intermediate  layer :  J/,  myxomatous  reticulum;  P,  papilla :  <S'. 
so-called  structureless  membrane.    Magnified  1000  diameters. 


enamel-organ  is  stored-up  material  for  the  benefit  of  the  growings 
enamel  itself,"  the  same  as  is  the  intermediate  layer. 

"  One  fact  will  strike  every  observer, — viz.  that  the  enamel  is 
seldom,  if  ever,  perfectly  symmetrical  in  the  growing  tooth, 
being  on  one  side  lu'oader,  to  the  extent  of  five  or  six  times, 
than  on  the  other;  sometimes  it  is  found  only  on  one  side  of  the 
developing  tooth,  while  on  the  other  nothing  but  delicate  fibrous 
connective  tissue  is  seen.  From  these  facts  we  must  conclude 
that  the  myxomatous  form  of  this  organ  is  by  no  means  a 
characteristic  or  an  absolute  requirement. 


DEVELOPMENT    OF    THE    EXAMEL. 


193 


"  How  can  we  explain  the  scantiness  of  this  organ  at  the  snm- 
luit  of  the  crown,  where  in  fnll  development  the  enamel  has 
the  greatest  diameter?  Can  the  original  enamel-organ,  even 
ever  so  broad,  sutfice  for  the  prodnction  of  the  whole  enamel  ? 
Is  not  the  enamel-coat  of  a  temporary  tooth  live,  nay,  ten  times  as 
broad  as  the  original  enamel-organ  ?  All  this  strongly  points  to 
the  con\'iction  that  the  budding  external  epithelium,  and  even  the 
primary  epithelial  peg,  must  furnish  material  for  the  building 


Fig.  119. 


Developixg  Tooth  op  Sheep's  Fcetus,  10  Cextimetebs  Long. 

D,  dentine  in  longitudinal  and  transverse  sections ;  A,  row  of  ameloblasts  at  rest ;  A^,  amelo- 
blasts  ibroken  up  into  medullary  tissue,  preceding  the  formation  of  enamel ;  I,  I,  intermediate 
layer;  M,  M,  myxomatous  enamel-organ ;  C,  capillary  blood-vessels.  Magnified  1000  diameters. 


of  enamel,  no  matter  what  the   intermediate  or   subsequent 
changes  of  this  tissue  may  be. 

"  In  conclusion,  I  wish  to  say  that  I  have  studied  the  develop- 
ment of  enamel  in  pigs  and  sheep,  and  have  found  the  relations 
therein  similar  to  those  in  the  enamel  of  the  human  tooth.  (See 
Fig.  119.)  In  the  sheep's  foetus,  ten  centimeters  long,  the  form- 
changes  of  the  ameloblasts  are    especially  pronounced,  since 

14 


194  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

shortly  before  the  appearance  of  the  enamel  a  splitting  into 
medullary  corpuscles  takes  place,  for  the  production  of  enamel- 
rods;  and  at  the  same  time,  at  their  distal  ends,  new  medullary 
corpuscles  show  themselves,  evidently  produced  at  the  expense 
of  the  intermediate  layer.  Both  the  last-named  layer  and  the 
blood-vessels  in  the  myxomatous  enamel-organ  John  Tomes 
observed  and  depicted  as  early  as  1848, — an  admirable  instance 
of  acute  observation  of  lasting  value." 


CHAPTER  XYI. 

FAULTY  DEVELOPMENT. 


During  the  formation  of  the  teeth,  constitutional  maladies  in 
the  possessor  have  an  important  influence  upon  the  calcification 
of  the  dentine  and  the  enamel.  Any  disturbances  in  the  proper 
supply  of  lime-salts  to  the  developing  dental  tissues  may  result 
in  a  malformation  of  the  crown  of  the  affected  tooth,  and  cause 
interruptions  in  the  process  of  calcification.  The  period  at 
which  defects  in  the  dentine  and  enamel  are  most  commonl}" 
produced,  is  after  birth.  We  may  also  observe  such  anomalous 
formations  of  the  crowns  of  teeth  as  the  consequence  of  constitu- 
tional diseases  of  the  mother  during  the  time  of  pregnancy,  or 
in  other  instances  they  may  be  inherited  from  the  father  or 
even  grandfather.  Upon  the  crowns  of  the  affected  teeth,  which, 
at  the  time  of  the  disease,  are  about  to  calcify,  we  notice  trans- 
verse ridges,  or  grooves  and  pits,  encircling  the  entire  crowns 
of  the  teeth,  such  deformity  being  the  more  marked  the  longer 
and  severer  the  disturbance  has  been.  The  color  of  these  teeth 
usually  is  dark  yellow, brown,  or  blue,  although  in  some  instances 
the  enamel  is  found  to  be  abnormally  white  and  opaque. 
Occasionally,  in  spots,  the  crowns  are  devoid  of  enamel,  and 
exceptionally  we  see  teeth  altogether  destitute  of  enamel.  In 
these  cases  the  exposed  dentine  is  of  a  dark-3"ellow  or  brownish 
color.  The  diseases  which  are  believed  to  produce  such  deformi- 
ties- are  syphilis,  rhachitis,  smallpox,  scarlet  fever,  measles,  and 
other  inflanimator}'  disturbances  of  the  skin  or  of  the  mucous 
membrane  of  the  alimentary  tract,  and  more  particularly  of 
the  oral  cavity.     Some  writers,  especially  J.  Hutchinson,  have 


FAULTY    DEVELOPMENT.  195 

attributed  sueli  deformities  of  the  dental  ti^5sues  mainly  to 
hereditary  syphilis.  At  present,  however,  it  is  acknowledged 
that  such  defective  formations  may  he  produced  hy  other 
diseases  which  temporarily  arrest  the  process  of  calciticatioa  of 
the  enamel  and  dentine.  It  is  believed  hj  J.  Tomes*  that 
deformities  resulting  from  constitutional  disturbances  of  the- 
mother  affect  in  the  infant  the  crowns  of  the  temporary  teeth,, 
which  are  found  in  such  cases  to  be  small,  abnormal  in  shape,, 
and  with  but  a  thin  coating  of  enamel.  This  author  also  states 
that  it  has  been  observed  that  children,  whose  permanent  teeth 
were  marked  by  deformed  enamel,  have  lost  them  early  through 
caries,  pericementitis,  or  periostitis.  In  these  instances,  it  is 
possible  that  the  defects  of  the  permanent  teeth  are  as  much  the 
cause  of  the  pericementitis  and  the  periostitis  as  the  result  of 
constitutional  ailments  of  the  mother. 

Furthermore,  such  distnrbances  occur  at  a  period  when  the 
enamel-organs  of  the  permanent  teeth  are  in  tlieir  first  stage 
of  development.  It  is  therefore  inexplicable  why  these  teeth 
should  be  marked  by  deformities,  while  the  crowns  of  the  tem- 
porary teeth,  at  that  time  in  progress  of  calcification,  are  usually 
normal  in  appearance.  The  author  has  seen  a  girl  about  eight 
years  of  age,  whose  remaining  temporary  teeth  were  all  marked 
by  deformed  enamel,  while  the  permanent  incisors  and  first  per- 
manent molars  were  possessed  of  a  normal  enamel.  "When  the 
disease  has  been  of  a  local  character,  it  may  occur  that  it  has 
affected  but  one  or  a  few  teetli  in  one  jaw  only,  while  all 
the  other  teetli  are  normal ;  although,  when  the  local  ailment 
has  extended  over  the  mucous  membrane  of  the  whole  mouth, 
all  the  teeth  that  are  in  process  of  calcification  will  be  affected. 
By  carefully  studying  the  time  when  the  crowns  of  the  teeth 
calcity,  we  are  enabled  to  judge  at  what  year  of  life  the  child 
was  ill.  (See  Fig.  120.)  Thus,  when  the  illness  has  occurred 
during  its  first  year,  we  notice  deformities  only  upon  the  cutting- 
edges  of  the  permanent  central  incisors  and  the  cusps  of  the 
first  permanent  molars;  while  the  disease  during  the  second 
year  of  life  will  mark  the  permanent  central  as  well  as  the 
lateral  incisors,  and  the  first  permanent  molars.  When  the  ill- 
ness of  the  child  happens  during  the  third  year,  the  deformity 
appears  about  in  the  middle  line  of  the  permanent  centrals,  and 
a  little  nearer  the  cutting-edge  of  the  lateral  incisors.     The 

*"  A  System  of  Dental  Surgery."     Philadelphia;  1873. 


196 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


Tig.  120.    (After  C.  N.  Peirce.) 


FAULTY    DEVELOPMEXT. 


197 


buccal  cusps  of  the  bicuspids  and  cuspids  may  either  escape 
injury  or  show  a  slight  defect,  but  the  first  permanent  molars 
usually  are  deformed  in  the  same  level  with  the  central  incisors. 
If  a  child  has  been  seriously  ill  during  the  fourth  year,  we  find 


Fig.  121. 


Right  Upper  Permaxext  Central  Incisor,  Mrs.  K.,  Forty-eight  Years  Old.    Ground. 

-B,  dentine,  lacking  enamel ;  .S",  secondary  dentine,  corresponding  to  bare  dentine ;  E,  narrow 
layer  of  pigmented  enamel;  /,  zone  of  interglobular  spaces;  P,  pnlp-tissue ;  C,  C,  calcareous 
deposits  in  the  pulp-tissue  ;  F,  dentine  in  immediate  vicinity  of  pulp-canal ;  0,  narrow  layer  of 
osteoid  cementum.    Magnified  6  diameters. 


198  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

the  defective  transverse  line  of  the  enamel  nearer  the  neck  of 
the  permanent  central  incisors,  at  about  the  middle  of  the  lat- 
erals, and,  in  the  case  of  the  cuspids  and  bicuspids,  on  the 
points  of  the  cusps,  while  the  first  permanent  molars  are  marked 
similarly  as  the  central  incisors, — i.e.,  near  the  necks.  Some- 
times it  occurs  that  children  are  attacked  hj  chronic  constitu- 
tional or  local  diseases  immediately  after  birth,  ^nd  lasting  up 
to  the  third  or  fourth  year  of  life.  In  such  an  instance  we  may 
notice  that  the  greater  portion  of  the  crowns  of  the  permanent 
central  and  lateral  incisors,  as  well  as  the  first  permanent  molars, 
present  a  crippled  appearance. 

While  the  above-named  maladies  usually  result  in  deformities 
of  the  crowns  of  the  teeth,  we  occasionally  meet  with  persons 
who  in  their  early  childhood  have  been  seriously  ill,  but  whose 
permanent  teeth  are  possessed  of  normal  enamel.  Although  it 
cannot  be  denied  that  some  of  these  deformities  are  the  result 
of  constitutional  ailments  of  the  child,  still  the  above  facts  to  a 
great  extent  corroborate  Abbott's  statement,  to  the  efiect  that 
faulty  formations  of  the  enamel  are  the  result  of  local  disturb- 
ances. 

An  instance  of  faulty  development  of  the  enamel  is  illustrated 
in  Fig.  121.  This  represents  the  right  upper  permanent  central 
incisor  of  a  lady  about  forty-eight  years  of  age,  who  knows  of 
no  disease  of  her  mother  or  of  her  oavu  childhood.  The  tooth 
became  loose  in  consequence  of  chronic  suppurative  pericemen- 
titis, and  was  extracted. 

The  enamel  is  narrow  and  intensely  pigmented.  It  is  miss- 
ing altogether  in  a  circumscriljed  spot  of  the  lingual  surface  of 
the  tooth  near  the  cutting-edge.  The  dentine  shows  a  zone  of 
interglobular  spaces  in  the  crown,  more  pronounced  on  the 
labial  than  on  the  lingual  surf  ice.  Corresponding  to  the  bare 
surface  of  the  dentine  there  is  a  marked  formation  of  secondary 
dentine,  holding  irregular  and  scanty  canaliculi.  The  pulp  is 
normal,  and  shows  a  number  of  calcareous  deposits,  especially 
at  the  l)eginning  of  the  pulp-canal.  The  cementum  is  altogether 
of  the  osteoid  type,  and,  although  lamellated,  is  devoid  of 
cement-corpuscles.  The  process  of  chronic  pericementitis  has 
not  affected  the  cementum,  which  nowhere  exhibits  the  l)ay-like 
excavations  characteristic  of  cementitis. 

An  instance  of  traumatism  of  considerable  interest  is  the 
tooth  depicted  in  Fig.  122.     It  is  a  right  upper  permanent  cen- 


FAULTY    DEVELOPMENT. 


199 


tral  incisor  of  a  youth  twelve  years  of  age,  removed  on  account 
of  the  disfigurement  as  well  as  the  overcrowded  condition  of  the 
dental  arch,  the  teeth  of  which  were  otherwise  normal.  The 
mother  of  the  boy  has  informed  me  that  the  child  always  has 


Fig.  122. 


Right  Upper  Central  Incisor  of  a  Boy  Twelve  Years  Old.    Ground. 

E,  irregular  pigmented  enamel  with  vestiges  of  channels;  C,  pigmented  channels  penetrating 
the  dentine;  B,  bare  dentine:  G,  globule  of  ill-ealcifled  dentine  ;  LP,  large  bifurcated  pulp- 
chamber  ;  SP,  small  central  pulp-chamber :  3',  nodule  of  pigmented  enamel :  »>■,  .S',  secondary 
dentine  at  the  borders  of  both  pulp -chambers :  i?,  narrow  laj-er  of  cementum.  Magnified  6 
diameters.- 


200  THE    ANATOMY    AXD    PATH0L0C4Y    OF    THE    TEETH. 

had  a  weak  constitution,  and  during  the  period  of  early  child- 
hood was  often  seriously  ill.  The  boy  did  not  have  the  upper 
central  incisors  till  he  was  four  years  of  age,  and  their  perma- 
nent successors  only  made  their  appearance  about  the  tenth 
year  of  age.  It  appears  to  be  improbable  that  general  or  local 
disturbances  should  have  influenced  the  malformation  of  this 
tooth.  On  the  other  hand,  there  is  a  strong  corroboration  of 
the  theory  of  traumatic  origin  of  the  anomalous  development  of 
the  tooth  under  consideration.  At  the  cutting-edge  we  observe 
four  channels,  or  rather  vestiges  of  channels,  where  a  series  of 
foreign  bodies  were  forcibly  thrust  into  the  enamel-organ 
shortly  after  birth,  or  at  least  during  the  first  year  of  life. 
Judging  from  the  arrangement  of  the  slighth'  devious  channels^ 
I  should  infer  that  the  foreign  bodies  were  pliable,  though 
rather  firm  and  pointed.  Such  bodies  are  the  bristles  of  a 
tooth-brush,  which  may  have  been  either  bitten  into  by  the 
infant,  or  may  by  other  accidental  means  have  obtained  entrance 
into  the  enamel-organ  of  the  tooth.  This  view  is  the  more 
plausible  since  we  find  a  detached  nodule  of  pigmented  enamel 
at  the  floor  of  the  central  pulp-chamber,  which  evidently  took 
origin  fi'oni  a  torn-off"  piece  of  the  enamel-organ.  A  portion 
of  the  dentine  being  destitute  of  enamel,  this  view  gains  the 
more  ground,  because  the  detached  nodule  of  enamel  corre- 
sponds in  its  devious  direction  to  the  other  tracts  of  the  channels. 
The  tooth  has  a  wide  bifurcated  pulp-chamber  and  a  small  cen- 
tral one,  both  exhibiting  narrow  layers  of  secondary  dentine. 
The  cementum  is  extremely  narrow  all  over  the  root,  and 
nowhere  developed  beyond  the  formation  normally  seen  at  the 
neck  of  the  tooth.  The  root  was  somewhat  compressed  and 
grooved  laterally.  The  arrangement  (>f  the  channels  and  the 
injuries  produced  in  the  enamel  are  illustrated  in  Fig.  123. 

The  enamel  is  colored  a  light  brown,  and  its  prisms,  besides- 
being  conspicuously  wa\w,  exhibit  irregularly-scattered  pigmen- 
tations. In  the  vicinity  of  the  channels  the  enamel  is  of  a  deep 
yellow-brown  color;  its  prisms  are  but  scantily  developed,  and 
in  most  places  are  replaced  by  a  deep-brown  amorphous  mass. 
The  dentine  along  the  borders  of  the  enamel-globules  and 
pegs  shows  slight  irregularities,  consisting  in  a  widening  of  the 
canaliculi,  or  in  coarse  conical  ofishoots  filled  with  granules 
of  lime-salts  emanating  from  the  enamel-pegs.  Around  the 
enamel-pegs  the  canaliculi  converge.     At  the  border  between 


FAULTY    DEVELOPMENT. 


201 


the  enamel  and  dentine  there  is  a  globular  formation,  deeply 
stained  with  an  ammoniacal  solution  of  carmin.  Higher 
powers  of  the  microscope  reveal  that  this  globule  is  an  anoma- 
lous formation  of  dentine.  (See  Fig.  124.)  The  basis-substance 
appears   finely  .  granular   and    arranged  concentrically.      It   is 

Fig.  123. 


Portion  of  Enamel  from  Cuttixg-Edge  of  Crown  of  Fig.  122. 

E,  enamel,  deeply  pigmented ;  C^.  vestige  of  channel  surrounded  by  a  dark  yellow-brown 
irregular  enamel ;  C",  vestige  of  channel  bifurcating  ;  G,  globule  of  ill-calcified  dentine  ;  D, 
normal  dentine.    Magnified  25  diameters. 


traversed  by  extremely  faint  dentinal  fibers  running  a  radiating 
course.  The  periphery  of  the  globule  is  surrounded  by  in- 
tensely-calcified globular  masses,  between  which  are  seen  inter- 
globular spaces  filled  with  protoplasm  and  granular  deposits  of 


202 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


lime-salts.  The  globules  are  pierced  by  scanty  and  irregularly- 
formed  dentinal  canaliculi,  wliicli,  however,  keep  the  general 
direction  of  those  of  the  normal  dentine.  Both  the. intensely- 
calcified  zone  around  the  globule,  and  the  normal  dentine,  are 
traversed  by  broad  routes  of  protoplasm  pervaded  with  coarse 
granules  of  lime-salts. 

Fig.  124. 


Globule  of  Ill-Calcified  Dentine  op  Fig.  122. 

(r.Sbasis-substance  uncalcified,  with  scanty  and  faint  dentinal  canaliculi ;  P,  globular  calca- 
reous deposits  around  tbe  uncalcified  basis-substance ;  T,  T,  tracts  filled  with  calcareous  granules ; 
B,  normal  dentine.    Magnified  500  diameters. 


That  the  protrusions  and  pegs  penetrating  the  dentine  really 
are  a  formation  of  enamel-tissue,  as  is  the  nodule  at  the  floor  of 
the"central  pulp-cavity  before  alluded  to,  is  proven  by  examina- 
tion with  higher  powers  of  the  microscope.     (See  Fig.  125.) 


FAULTY    DEVELOPMENT. 


203 


Furthermore,  we  notice  enamel-prisms  of  an  extremely  devious 
course,  the  deviousuess  being  most  pronounced  in  the  center  of 
the  peg,  where  a  number  of  transverse  sections  of  enamel- 
prisms  are  met  with.  Instead  of  such  transverse  sections,  we 
frequently  notice  amorphous   and    deeply-pigmented  granular 

Fig.  125. 


^  ^^  ^  "^ 


Portion  of  Ixterzoxal  Later  betweex  Destine   and  Enamel  of  Cutting-Edge  of 

Fig.  122. 

G,  G,  globular  protrusions  of  pigmented  enamel;  T,  tract  of  anomalous  enamel;  A,  amor- 
phous, deeply  pigmented  masses,  replacing  transverse  sections  of  enamel-prisms;  H,  highly 
refractive  rims  between  enamel  and  dentine  ;  I>,  normal  dentine.    Magnified  500  diameters. 


masses,  which  probably  are  the  result  of  crushed  ameloblasts. 
The  yellow-brown  color  of  the  anomalous  formation  of  the 
enamel  is  everywhere  due  to  the  presence  of  such  amorphous 
masses,  whereas  the  enamel-prisms  appear  of  a  lighter  dusky- 


204  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

brown  color.  There  is  but  little  doubt  that  the  pigment  of  the 
masses  is  due  to  a  hemorrhage  produced  at  the  time  of  the 
injury.  A  noteworthy  feature  is  the  presence  of  an  intensely- 
calcified  rim  between  the  globules  and  the  pegs  of  the  enamel 
and  the  dentine,  which  is  traversed  by  the  bifurcations  of  the 
dentinal  canaliculi. 

The  writer  has  observed  an  interesting  incident  of  faulty 
development  in  a  family  of  four  children  and  two  grandchildren. 
The  four  children  have  no  enamel  upon  their  permanent  teeth, 
while  the  teeth  of  both  parents  were  covered  with  normal 
enamel.  The  teeth  of  all  the  children  were  abnormally  small, 
and  the  incisors  and  cuspids  even  smaller  than  ordinary  tem- 
porary teeth.  Their  external  surface  is  smooth,  of  a  dark-yellow 
color,  and  not  abnormally  sensitive  to  thermal  changes.  The 
molars  mostly  have  the  form  of  a  lower  first  temporary  molar, 
while  the  bicuspids  are  of  normal  form,  but  quite  small.  The 
cusps  of  all  the  molar  teeth,  when  they  made  their  appearance 
through  the  gums,  were  quite  sharp,  and,  becoming  a  source  of 
irritation  to  the  tongue  and  cheeks,  they  had  to  be  rounded  ofi". 
These  teeth  soon  decayed  where  the  pointed  cusps  had  been 
removed,  and  the  inner  portion  of  the  dentine  was  extremely 
sensitive  to  the  touch  of  the  bur.  The  writer  has  lately  seen 
the  two  grandchildren  of  this  family,  one  of  which  is  five  and 
a  half,  the  other  six  years  of  age.  The  latter  child  has  normal 
temporary,  and,  as  far  as  erupted,  good  permanent  teeth,  while 
the  former  has  inherited  the  faulty-developed  teeth  of  his  father. 
This  child,  although  only  five  and  a  half  years  of  age,  had  its 
upper  and  lower  permanent  central  incisors  and  the  first  per- 
manent molars  fully  erupted.  The  remaining  temporary  teeth 
are  the  smallest  teeth  the  writer  has  ever  seen  in  any  child's 
mouth.  Their  enamel,  with  the  exception  of  the  upper  second 
temporary  molars,  appears  to  be  normal.  The  latter  four  teeth 
each  exliibit  two  pointed  cusps,  and  seem  to  be  devoid  of 
enamel.  The  four  permanent  molars,  which  in  general  size  and 
shape  are  nearer  normal  than  those  of  his  father's,  are  sur- 
mounted by  four  or  five  cusps  respectively,  and  appear  to  be 
entirely  devoid  of  enamel.  The  upper  and  lower  permanent 
central  incisors  exhibit  a  bright-yellow  color,  and  are  also  much 
larger  than  those  of  the  father,  while  their  surfaces  seemingly 
lack  enamel.  They  are  marked  by  transverse  grooves,  princi- 
pally upon  their  labial  surfaces. 


FAULTY    DEVELOPMENT. 


205 


I  shall  make  use  of  two  valuable  contributions  to  this  topic 
by  Frank  Abbott.* 

The  first  deals  with  anomalous  occurrences  in  the  enamel,  as 
follows  : 

"I.  Anomalous  Relation  between  Dentine  and  Enamel. — In 
examining  a  large  number  of  specimens  of  ground  teeth,  I  met 
with  formations  in  two  instances  which  are  to  be  considered  as 
rather  anomalous,  though  not  strictly  pathological.  In  one 
instance,  that  of  a  temporary  molar,  there  was  on  the  buccal 


Fig.  126. 


Protrusion  of  Dentine  into  Enamel. 

E,  enamel ;  D,  dentine ;  H,  hill  of  dentine  with  fluted  summit ;  P,  protoplasmic  bodies  in 
the  dentine.    Magnified  400  diameters. 

surface  a  protrusion  of  dentine  into  the  enamel  with  a  fluted 
surface,  or  a  surface  fluctuating  in  a  series  of  bay-like  excava- 
tions. This  fluting  was  present  also  at  the  junction  of  the 
dentine  with  the  enamel  in  general,  but  not  so  marked  as  in 
this  protruding  spot.  The  center  of  this  protrusion  was  occu- 
pied by  an  eccentric  protoplasmic  formation,  differing  in  shape 
from  the  ordinary  interglobular  spaces.  The  dentinal  fibers  at 
the  periphery  were  bifurcated  in  the  usual  manner,  but  very 

*  "Studies  of  the  Pathology  of  Enamel  of  Human  Teeth,  with  Special  Eefer- 
ence  to  the  Etiology  of  Caries."     Dental  Cosmos,  1885. 


20(3 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


few  of  them  penetrated  the  enamel.  The  portion  of  the 
enamel  nearest  to  the  protrnsion  was  destitute  of  prisms,  while 
in  the  immediate  vicinity,  again,  of  this  portion  such  pr'sms 
were  traceable  almost  in  contact  with  the  dentine.  The  zone 
immediately  above  the  protrusion  was  but  slightly  brownish, 
whereas  the  prisms  of  the  enamel  exhibited  a  very  distinct 
brown  pigmentation. 

Fig.   127. 


#i^ 


'jji)/"' " 

.f  .T'^^^VS    /  '^  "I'll  o 

/I 

44 — ^*+-t. 


Wl^ 


'  Protrusion  of  Dentine  into  Pathological  Enamel. 

E,  enamel ;  D,  dentine  ;  G,  granular  enamel ;  A,  summit  of  the  dentine  ;  S,  sloping  borders 
of  the  granular  enamel.    Magnified  200  diameters. 


"  In  a  second  case,  that  of  a  permanent  cuspid,  a  protrusion 
of  dentine  was  observed,  as  in  the  former  instance,  on  the 
buccal  surface  near  the  edge,  occupying  nearly  one-half  of  the 
breadth  of  the  enamel.  This  protrusion  was  of  a  conical  shape, 
and  without  a  distinct  boundary,  but  blended  with  an  oblong 
field  of  enamel  of  quite  remarkable  structure.  The  dentinal 
canaliculi  exhibited  at  their  peripheral  portions  numerous  bi- 


FAULTY    DEVELOP-ME^JT.  207 

furcations,  and  terminated  in  small  pear-shaped  enlargements, 
many  of  which  conld  be  traced  in  connection  with  dentinal 
fibers,  whereas  the  most  peripheral  ones,  owing  to  their  devious 
course,  looked  isolated.  The  adjacent  enamel  showed  but  very 
indistinct  rods,  the  main  mass  of  the  enamel  being  occupied  by 
brownish  globular  fields,  separated  from  one  another  by  irreg- 
ular interstices  closely  resembling  the  interglobular  spaces  of 
dentine,  though  of  considerably  smaller  size.  The  deepest  pig- 
mentation and  the  largest  number  of  such  interprismatic  spaces 
occurred  along  the  periphery  of  this  anomalous  formation, 
especially  toward  the  outer  surface  of  the  enamel.  The  yicinity 
of  the  enamel  proper  was  marked  by  the  presence  of  slightly  pig- 
mented rods,  more  wavy  in  their  course  than  is  normal.  Toward' 
the  dentine  the  anomalous  formation  was  sloping,  and  the  line  of 
demarcation  between  the  normal  and  anomalous  enamel  exhib- 
ited either  brown  and  yery  wayy  prisms  or  small  inferprismatic 
spaces,  decreasing  in  diameter  the  nearer  they  approached  to  the 
dentine.  I  wish  to  emphasize  and  call  particular  attention  to 
the  fact  that  the  dentine  of  this  tooth  was  nowhere  traversed  by 
interglobular  spaces,  the  anomalous  construction  being  confined 
to  the  enamel. 

"II.  Stratification  of  Enamel. — It  is  known  that  dentine, 
without  exhibiting  pathological  features,  yet  slightly  deviating 
from  its  normal  structure,  is  sometimes  composed  of  strata  that 
are  more  or  less  distinctly  marked,  and  are  altogether  independ- 
ent of  the  formations  known  as  secondary  dentine.  We  often 
meet  with  similar  formations  in  the  enamel.  We  observe, 
varying  in  width  and  more  or  less  sharply  marked  Ijy  a  straight 
line,  layers  which  in  longitudinal  sections  of  teeth  are  concen- 
tric, the  broadest  part  corresponding  to  the  cusps,  the  narrowest 
to  the  neck  of  the  tooth. 

"  At  the  outer  periphery  of  the  enamel  there  may  occur 
strata,  which,  contrary  to  the  general  construction  as  above 
described,  are  broadest  toward  the  neck  and  narrowest  toward 
the  cusp,  though  never  reaching  its  summit.  In  transverse 
sections  the  enamel  shows  simply  concentric  lines,  separating 
from  one  another  layers  of  greatly  varying  diameters.  With 
higher  powers  of  the  microscope  we  ascertain  the  fact  that  the 
lines  of  stratification,  as  a  rule,  do  not  alter  the  general  course 
of  the  enamel-prisms, — in  other  words,  a  single  enamel-prism 
will  show  an  oblique  line  of  demarcation,  corresponding  to  the 


208  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

Fig.   128. 


iHl 

m 


Diagram  of  Stratification  op  Enamel. 

P, "pulp-chamber ;  B,  denting ;  CL^,  CL^,  CL^,  CL\  cusp-layers  of  enamel ;  NL\  NL^,  neck- 
layers'of  enamel. 


FAULTY    DEVELOPMEXT.  '  209 

general  line  of  stratification,  without  being  altered  in  its  con- 
struction or  its  course.  An  exception  to  this  rule  will  occur 
only  at  the  peripheral  portions  of  enamel,  occupied  hy  the 
tapering  ends  of  the  ahove-described  secondary  strata,  which  I 
would  like  to  term  neck-layers,  in  contradistinction  to  the  central 
casp-Vvjers.  The  tapering  ends  of  the  neck-layers  may  exhibit 
enamel-rods,  almost  parallel  with  the  surface  of  the  enamel,  a 
feature  which  is  never  seen  at  the  outer  periphery  of  the  cusp- 
layers,  where  the  enamel-rods  are  invariably  directed  more  or 
less  perpendicularly  to  the  surface. 

••  An  understanding  of  the  stratification  of  the  enamel  is  of 
the  utmost  importance  in  aiding  the  understanding  of  its  pig- 
mentation and  granulation.  As  I  will  show  later  on,  both  the 
pigmentation  and  granulation  correspond  to  the  general  strata 
of  the  enamel,  thus  showing  in  longitudinal  sections  of  teeth 
a  fan-like  appearance. 

'•  It  can  scarcely  be  doubted  that  the  stratification  of  this 
tissue  is  in  close  relation  to  the  history  of  its  development.  A\^e 
know  that  the  first  appearing  enamel-cap  of  temporary  teeth,  in 
the  seventh  month  of  intra-uterine  life,  has  the  configuration  of 
the  innermost  cusp-layer,^ — i.e.,  it  is  broadest  in  the  direction  of 
the  future  cusp,  and  tapers  toward  the  future  neck  of  the  tooth. 
It  seems  reasonable  to  assume  that  the  subsequent  layers  of 
enamel  form  on  the  plan  of  the  first,  but  there  may  be  a  tempor- 
ary stoppage  of  its  construction,  due.  perhaps,  to  slight  ailments 
of  the  mother  before  delivery  of  the  child,  or  slight  ailments  of 
the  infant  after  delivery,  which  causes  interruptions  in  its  organi- 
zation. Slight  ailments  of  a  general  nature  will  not  interfere 
with  the  final  result  of  an  otherwise  sound  enamel:  whereas 
severe  ailments,  particularly  local  ones,  may  lead  not  only  to 
stratification,  but  to  a  decidedly  pathological  condition,  which  I 
have  before  called  pigmentation  and  granulation.  These  condi- 
tions invariably  involve  a  deficient  deposition  of  lime-salts. 

"III.  Anomalous  Arrangement  of  the  Enamel-Rods. — In 
normal  enamel,  longitudinal  sections  "will,  in  the  majority  of 
cases,  exhibit  slightly  wa^-y  rods,  interlaced  by  comparatively 
small  bundles,  cut  in  a  transverse  direction.  Toward  the  periph- 
ery the  curvatures  of  the  rods  gradually  become  less,  until, 
when  close  to  the  surface,  they  present  a  nearly  straight  course. 
I  have  never  seen  transverse  sections  of  enamel-rods  directly  in 
contact  with  the  interzonal  layer. 

1-5 


210  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

"  Deviations  from  this  rule  seem  to  be  rare.  Where  they  exist,, 
the  enamel-rods  seem  to  lack  all  regularity  in  their  arrangement. 
It  may  occur  that  close  to  the  interzonal  layer  the  enamel-rods 
show  extensive  fields  occupied  by  these  transverse  sections,  which 
gradually  blend  with  oblique  and  longitudinal  ones,  producing 
a  wavy  appearance,  to  such  an  extent  that  beautiful  figures  arise,. 
reminding  one  of  the  grain  of  lignum-vitce.  Still  more  compli- 
cated figures  arise  if  the  transverse  bars  of  the  longitudinal 
rods  are  unusually  conspicuous.  In  such  enamel  it  may  occur 
that  the  curvatures  of  the  rods  remain  very  marked  up  to  the 
surface ;  and,  consequently,  groups  of  transverse  sections  may 
be  seen  directly  at  the  outer  surface. 

"  Enamel  of  this  description  may  be  seen  only  on  one  portion 
of  the  tooth,  while  the  rest  is  normal.  In  all  my  specimens, 
pigmentation  is  combined  with  this  curly  appearance  of  the 
enamel-rods  as  a  marked  feature,  and  the  interstices  between 
the  rods  are  a  trifle  wider  than  normal.  Both  of  the  latter 
features  must  imply  a  deficient  calcification,  and,  consequently,, 
extreme  brittleness.  It  is  very  ditficult  to  obtain  perfect  speci- 
mens of  such  enamel.  The  dentine  subjacent  to  such  anomalous 
formations  is  freely  supplied  with  interglobular  spaces,  which 
fact  is  likewise  a  sign  of  deficient  calcification. 

"  IV.  Deficient  Calcification  of  the  Enamel,  without  Pigmen- 
tation.— The  friability  alluded  to  under  the  previous  heading 
is  in  some  instances  very  marked, — so  much  so  that  it  is  impos- 
sible to  obtain  an  unbroken  slab  of  a  tooth,  even  with  the  finest 
grinding-stones.  With  low  powers  of  the  microscope  we 
observe  that  the  broken  ends  of  the  enamel-rods  look  as  if  cor- 
roded, or  as  if  some  of  them  had  been  displaced  or  torn  ofi"  by 
the  process  of  grinding.  ISTeither  pigmentation  nor  an  anoma- 
lous course  of  the  enamel-rods  is  necessarily  connected  with 
such  a  condition  of  the  tooth.  The  most  striking  feature,  how- 
ever,— a  feature  visible  even  with  low  powers, — is  that  the 
enamel-rods  are  unusually  narrow,  the  interstices  between  them 
unusually  wide,  and  their  tenants,  the  enamel-fibers,  very  promi- 
nent. The  cross-lines  of  the  enamel-rods  are  likewise  consider- 
ably widened  and  irregular,  so  that  the  fields  of  basis-substance 
look  unusually  small  and  irregular.  The  reticulum  in  the 
immediate  vicinity  of  the  interzonal  layer  is  also  unusually 
prominent. 

"  Such  a  condition  of  the  enamel  may  occur  both  in  tempo- 


FAULTY    DEVELOPMENT. 


211 


rarv  and  permanent  teeth,  and  may  be  combined  ^vith  pigmenta- 
tion. It  is  a  feature  of  such  deficient  enamel  that  it  readily 
stains  with  an  ammoniacal  sokition  of  carmin,  something  that 
normal  enamel  will  not  easily  do.  The  subjacent  dentine,  under 
such  conditions,  may  either  be  perfectly  developed,  as  before 
stated,  or  be  deiicientin  its  formation,  as  shown  by  the  presence 
of  more  or  less  numerous  interglobular  spaces. 

"  All  clinicians  have  observed,  in  the  enamel  of  teeth,  con- 

FiG.  129. 


Extremely  Ikregui.ae  Course  of  Rods  tx  Slightly-Pigmested  Examel. 

The  longitudinal  rods  deviating  to  a  great   extent  from  the  field  of  the  specimen,  show  • 
oblique  and  transverse  sections.     The  interstices  are  widened  and  contain  conspicuous  enamcl- 
iibers.    Magnified  1200  diameters. 


genital  white  or  yellow  spots,  which,  if  broken  into,  are  found 
to  be  of  the  consistence  of  chalk.  Such  spots  have  been  termed 
'  white  decay,'  although  they  do  not  correspond  to  the  process 
of  caries  as  we  usually  understand  it.  They  mean  nothing  but 
deficient  calcification.  Again,  all  clinicians  have  seeo  teeth 
across  which  runs  a  row  of  pit-holes,  in  the  bottom  of  which 
depressions,  in  many  instances,  no  enamel  is  to  be  found.  This 
condition,  also,  is  always  congenital,  and  closely  related  in  its 


212  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

origin  to  pigmentation  and  the  white  or  yellow  spots.  In 
other  instances  an  originally  smooth  enamel  is  mutilated 
mechanicallv  by  the  process  of  mastication,  with  the  result  of  loss 
of  substance,  with  abruptl}'  broken,  jagged  edges.  Again,  we  see 
teeth  with  a  great  portion  of  their  crowns  covered  by  a  brown- 
ish-yellow substance  in  place  of  enamel,  this  substance  being  so 
soft  as  to  be  easih'  remoyed,  leaving  the  dentine  bare  of  its 
covering  and  extremely  sensitive  to  the  touch  of  an  instrument, 
the  pressure  of  food  in  mastication,  etc.  These  conditions, 
again,  are,  in  most  instances  at  least,  connected  with  the  presence 
of  pigmentation  and  the  white  or  yellow  spots.  "We  might 
call  them  exaggerated  cases  of  the  same  condition.  Obviously 
these  congenital  defects  are  dependent  upon  deficient  deposition 
of  lime-salts  in  the  basis-substance,  rendering  the  enamel  less 
resistant  and  more  friable. 

"V.  Pigmentation  of  Enamel. — One  of  the  most  common 
anomalous  conditions  of  the  enamel  is  its  pigmentation.  Some- 
times it  is  so  slightly  marked  that  the  naked  eye  discovers  only 
a  slight  yellow-brown  discoloration :  in  other  instances  it  is 
quite  prominent  and  readily  discernible.  Correspondingl}', 
specimens  of  such  teeth  under  the  microscope  will  exhibit  either 
a  dim  yellow  tint  in  the  enamel  or  a  marked  brown  discol- 
oration. The  pigmentation  may  occur  either  in  non-stratified 
or  in  stratified  enamel.  In  the  first  instance  there  is  no  demar- 
cation of  the  brown  spot  toward  the  colorless  enamel ;  only 
faintly-marked  oftshoots  of  the  main  spot,  tapering  toward  the 
dentine,  and  running  in  an  oblique  direction,  will  indicate  the 
fact  that  pigmentation  has  occurred  during  its  formation.  In 
the  second  instance,  on  the  contrary,  if  pigmentation  invades 
stratified  enamel,  there  is  a  close  relationship  between  the  two, 
inasmuch  as  the  deepest  stain  invariably  corresponds  to  the 
boundary  line  of  the  strata,  tapering  toward  the  neck,  and 
gradually  fading  toward  the  proximal  end  of  each  stratum. 
Thus,  in  longitudinal  sections,  a  beautiful  fan-like  configuration 
is  produced. 

"  The  pigmentation  may  invade  all  layers  of  the  enamel,  often 
being  more  marked  in  the  deeper  than  in  the  superficial  por- 
tions. Higher  powers  of  the  microscope  reveal  the  following 
facts :  First,  that  the  brown  discoloration  concerns  the  basis- 
substance  of  the  enamel-rods  only.  Secondly,  that  the  inter- 
stices between  the  pigmented  enamel-rods  are  widened, — not 


FAULTY    DEVELOPMENT. 


213 


merely  to  seeming,  and  in  consequence  of  the  contrast  in  color, 
but  because  of  a  deiiciency  in  the  formation  of  the  basis-sub- 
stance. Thirdly,  that  the  transverse  lines  of  the  enamel-prisms 
likewise  are  (at  least  in  many  instances)  enlarged.  Fourthly, 
that  the  enamel-fibers  and  their  lateral  offshoots  are  more  con- 
spicuous than  in  normal  enamel,  and  more  so  even  than  in  the 
enamel  of  temporary  teeth,  and  in  many  places  distinctly 
beaded.  Pigmented  portions  of  the  enamel  are  rather  prone  to 
take  up  a  red  stain  on  being  treated  with  an  ammoniacal  carmin 
solution. 

Fig.  130. 


iiii|i||iil4lit!lil4ii^ 


J) 


Pigmented  axd  GEAxrLAE  Examel. 

D,  dentine  ;  EE,  layer  of  slightly  pigmented  rods  broken  off;  EG,  layer  of  highly  pigmented 
and  granular  enamel ;  EP,  stratified  pigmented  enamel.    Magnified  400  diameters. 

"  As  to  the  origin  of  the  brown  discoloration,  I  have  to  say, 
as  a  suggestion  simply,  that  at  the  time  of  the  formation  of  this 
tissue  there  must  have  been  a  disturbance  in  the  enamel-organ 
which  interfered  with  the  proper  construction  of  the  basis-sub- 
stance and  the  deposition  of  lime-salts.  What  this  disturbance 
really  was,  I  am  unable  to  say.  Many  pigments  of  the  body  de- 
pend upon  and  are  closely  related  to  the  coloring-matter  of  the 
blood.     I  am  loth,  however,  at  this  time,  to  attribute  pigmen- 


214  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

tation  of  enamel  to  the  extravasation  of  blood-corpuscles  or 
diff'usion  of  the  coloring-matter  of  the  blood.  Careful  studies 
in  the  history  of  the  development  of  this  tissue  must  be  made, 
before  an  attempt  at  a  solution  of  this  question  will  be  admis- 
sible. One  point  I  am  positive  about,  however,  is  that  this  pig- 
mentation is  congenital,  invading  temporary  as  well  as  perma- 
nent teeth.  Acquired  pigmentation  of  enamel  seems  to  be  ot 
comparatively  I'are  occurrence,  except  as  a  result  of  caries.  I 
have  seen  pigmentations  of  its  surface,  of  a  deep  orange  color, 
not  penetrating  the  enamel-tissue  in  the  least.  Caries  on  the 
surface  often  causes  an  orange  discoloration,  diffused  and  fading 
toward  the  normal  portions.  Several  of  my  specimens  plainly 
show  an  invasion. of  the  enamel  by  caries,  on  spots  pigmented 
congenitally ;  secondarily,  an  orange  diffused  discoloration  has 
taken  place,  and  here  the  enamel  is  likewise  prone  to  take  up 
the  carmin  stain ;  thus  beautiful  shadings  of  brown,  orange, 
and  red  are  to  be  seen,  the  brown  being  congenital  substances, 
the  orange  acquired,  and  the  red  artificial.  What  chemical  may 
lead  to  an  acquired  pigmentation  or  discoloration  of  the  enamel 
I  caunot  say. 

"  VI.  Granulation  of  Enamel. — Under  this  heading  I  propose 
to  describe  a  peculiar  abnormality,  which,  so  far  as  my  speci- 
mens indicate,  is  by  no  means  rare.  It  consists  of  pear-, 
spindle-,  and  club-shaped  spaces  in  the  middle  of  the  substance 
of  the  enamel.  Such  spaces  were  known  to  exist  heretofore  at 
the  junction  of  the  dentine  and  enamel  only.  They  may  appear 
in  pigmented,  and  invariably  do  in  stratified,  enamel;  the  strati- 
fication in  the  latter  instances  being  due  to  their  presence. 
Club-shaped  spaces  may  appear  at  the  distal  boundary  of  one  ol 
the  cusp-layers,  or  there  may  be  several  rows  of  such  spaces, 
varying  in  extent  and  degree,  but  it  sometimes  occurs  that  only 
the  outermost  cusp-  or  neck-  layers  are  freely  supplied  with  them, 
whereas  the  rest  of  the  enamel  is  normal  or  more  or  less  pig- 
mented. 

"  Higher  powers  of  the  microscope  demonstrate  that  the 
spaces  are  enlargements  of  the  interstices  between  the  prisms 
and  the  tenants  of  the  interstices.  The  enamel-fibers  are  in 
direct  connection  with  the  contents  of  the  spaces, — i.e.,  with 
living  matter.  The  spaces,  at  their  stem-like  beginnings,  run, 
accordingly,  parallel  with  the  interstices;  but  in  their  broader 
portions  ma^y  cross  the  enamel-prismS  in  different  directions. 


FAULTY    DEVELOPMENT. 


215 


If  they  are  few  in  number  tliey  may  protrude  from  the  bound- 
ary Ime  of  a  cusp-layer,  and  penetrate  the  adjacent  cusp-layer 
obliquely  to  the  main  direction  of  the  enamel-rods.  In  this  in- 
stance I  could  trace  the  connections  of  the  enamel-fibers  even 
with  the  club-shaped  ends  projecting  into  the  neighboring  cusp- 
layer.  If  these  spaces  are  present  in  large  numbers,  the  enamel, 
with  lower  powers  of  the  microscope,  will  look  dark  and  granu- 
lar; hence  the  name,  'granulation  of  enamel,' which  I  have 


given  it. 


Pig.  131. 


Geanular  axd  Slightly  Pigmented  Examel. 

Club-,  spindle-,  pear-shaped,  and  irregular  spaces  at  the  boundary  of  a  cusp-layer  in  the 
middle  of  enamel.    Magnified  1200  diameters. 


"  Fig.  127  represents  this  condition  of  granulated  enamel, 
with  a  low  power. 

"  Fig.  131  shows  the  condition  under  a  high  power. 

"•  In  stratified  and  granular  enamel,  single  strata  may  be  pro- 
duced by  an  interruption  of  the  pigmented  enamel-rods,  by  con- 
vex ends  directed  toward  the  adjacent  peripheral  cusp-layer. 
(See  Fig.  130.) 

"  The  interprismatic  spaces  of  the  enamel  bear  some  resem- 
blance to  the  interglobular  spaces  of  the  dentine.     I  have  seen 


216  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

both  conditions  in  a  highly-marked  degree  present  in  one  of  my 
specimens.  Whenever  these  interprismaiic  spaces  are  present 
along  the  border  of  a  cusp-layer,  they  considerably  lessen  the 
degree  of  consistence  of  the  enamel,  which,  npon  being  ground, 
easily  breaks  oif  along  the  dark  granular  line. 

"  The  nature  of  the  mterprismath:  spaces  is  plain  enough. 
They  mean  an  incomplete  formation  of  the  enamel,  owing  to 
some  deficient-y  of  function  in  the  enamel-organ  during  its  for- 
mation. Obviously,  not  only  the  basis-substance  is  deficient, 
but  also  the  amount  of  lime-salts  is  considerably  less  than  nor- 
mal; hence  its  brittleness  and  proneness  to  decay. 

"  Under  the  foregoing  headings  I  have  described  a  number 
of  anomalous  conditions  of  the  enamel,  which,  at  least  so  far 
as  stratification,  pigmentation,  and  granulation  are  concerned, 
mean  a  deficient  formation  of  the  basis-substance,  together  with 
decreased  deposition  of  lime-salts.  These  conditions  are,  in  my 
judgment,  of  the  utmost  importance  in  the  etiology  of  caries. 
Ailments  either  of  the  mother  during  gestation  or  of  the  infant 
in  the  earliest  periods  of  life,  obviously  cause  such  anomalies  in 
this  tissue.  These  ailments  are  known  to  occur  far  more  fre- 
quently in  refined  people,  debilitated,  as  it  were,  by  civilization, 
than  in  strong,  hard-working,  plain-living  people,  continually 
engaged  in  a  struggle  for  life.  Thus,  I  have  directly  demon- 
strated and  anatomically  shown,  in  a  measure,  at  least,  the 
reasons  why  refined  people  are  far  more  subject  to  caries  of 
the  teeth  than  people  lacking  such  refinement." 

The  other  contribution,  by  Frank  Abbott,  to  the  knowledge 
of  faulty  development  of  enamel  is  Congenital  Defects  in  Enamel.^ 

"  Every  dental  practitioner  is  more  or  less  familiar  with  the 
condition  of  imperfect  or  defective  enamel  upon  the  crowns  of 
permanent  teeth  (more  especiall}^  the  incisors  and  first  molars), 
which  I  propose  to  consider  under  the  above  heading.  These 
imperfections  usually  concern  the  summit  of  the  crown  or  its 
vicinity.  We  see  upon  an  otherwise  well-developed  crown  an 
almost  circular  ridge,  above  which  the  enamel  appears  of  a 
grayish-brown  color,  and  in  the  shape  of  numerous  pointed, 
thorny  projections,  the  masticating  surface  of  molars  appearing 
as  if  provided  with  numerous  minute  stalactites  or  stalagmites. 
(See  Fig.  132.) 

*  Dental  Cosmos,  1891. 


FAULTY    DEVELOPMENT. 


217 


"  In  some  cases  there  are  only  a  few  blunt  or  pointed  protru- 
sions of  enamel,  between  which  the  dentine  is  entirely  destitute 
of  such  covering.  In  others  the  dentine  is  nearly  covered  with 
enamel,  leaving  rows  of  small  round  or  oblong  holes  through  it 
to  the  dentine.  These  features  appear,  as  before  stated,  only  in 
permanent  teeth,  and  very  seldom  are  any  except  the  incisors 
and  first  molars  involved.  Whether  or  not  the  complete  absence 
of  enamel  from  the  crowns  of  incisors,  as  is  sometimes  seen,  is 

Fig.  132. 


CONGENITALLY  IMPERFECT   CkOWS   OF   LOVTEE  MOLAB. 

^■,  shortened  crown ;  C,  C,  cones  of  enamel ;  1),  dentine  without  enamel  covering.    Magnified 
4  diameters. 


of  the  same  nature,  and  due  to  the  same  causes,  I  am  not  pre- 
pared to  say,  although  it  seems  probable. 

"  In  looking  with  the  naked  eye  at  a  longitudinal  section 
through  a  molar,  aifected  as  just  described,  we  at  once  recognize 
the  deficiencies  of  enamel,  the  stalactite  or  stalagmite  appear- 
ance, and  the  shortening  of  the  crown  by  about  one-eighth  of 
an  inch,  caused  by  these  deficiencies. 

"  These  blunt  and  pointed  elevations  are  made  up  partly  of 


218 


THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


healthy-looking  and  partly  of  a  yellowisli-brown  enamel.  Be- 
tween the  elevations  are  areas  partly  covered  by  an  extremel}'^ 
thin  layer  of  enamel  and  partly  destitute  of  it.  By  grinding 
the  crown  of  such  a  tooth  in  longitudinal  section  for  microscopi- 
cal examination,  the  masticating  surface  presents  an  extremely 
striking  image.     (See  Fig.  133.) 

"A  well-developed,  though  slightly-pigmented,  enamel  is  seen 
to  be  gradually  tapering  toward  the  masticating  surface,  show- 

FiG.   133. 


Section  or  Masticating  Surface,  shotting  Partial  Covering  of  Enamel. 

E,  well-developed  enamel ;  L,  isolated  lumps  of  enamel ;  D.  D,  dentine  :  /,  1.  interglobular 
spaces.    Magnified  100  diameters. 


ing  marked  deficiencies  of  the  outermost  layer.  These  deficien- 
'  cies  consist  of  conical  depressions  at  the  surface  and  granula- 
tions near  it.  Obviously  this  condition  was  caused  by  an  incom- 
plete calcification  of  the  enamel,  iTom  the  fact  that  it  has  taken 
up  or  absorbed  a  deep  brown  pigmentation.  The  tapering 
layer  of  enamel  stops  abruptly,  leaving  the  dentine  entirely  un- 
covered, as  is  seen  in  several  places;  besides,  there  are  irregular 
hilly  protrusions  of  an  enamel  of  a  deep  brown  color.  These 
are  the  protrusions  furnishing  to  thegrinding-surfacethe  appear- 


FAULTY    DEVELOPMENT. 


219 


ance  of  groups  of  stalactites.  Slabs  exposed  to  the  action  of  a 
half  per  cent,  solution  of  chloride  of  gold  for  one  hour,  exhibit 
a  dark  violet  color  of  the  dentine  in  the  crevices  between  the 
enamel-lumps,  which  means  that  a  portion  of  the  lime-salts  has 
been  dissoh^ed  out,  although  no  destruction  of  the  organic  por- 

FiG.   134. 


Isolated  Lump  of  Enamel,  Very  Imperfect. 

P,  P,  P,  protoplasmic  projections  into  the  enamel  from  the  dentine ;  C,  transverse  section  of 
enamel-prisms  ;  B,  dentine.    Magnitied  500  diameters. 

tion  of  the  dentine  has  taken  place.  At  the  usual  distance  from 
the  mterzonal  layer  are  seen  interglobular  spaces. 

"  L*et  us  magnify  a  lump  of  enamel  in  this  locality  live  hun- 
dred diameters.     (See  Fig.  134.) 

"  "We  notice  in  this  specimen  narrow  prisms,  markedly  wavy, 
and  interrupted  by  faint  concentric  striations.     The  prisms,  as 


220 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


usual,  do  not  reach  the  surface  of  the  dentine,  but  at  a  given 
distance  from  it  they  are  replaced  by  irregular  angular  pieces. 
The  outermost  portion  of  the  lump  is  of  a  dark  brown  color. 
Penetrating  the  enamel  at  varjing  heights  are  seen  numerous 
pear-shaped  prolongations  of  the  dentinal  canaliculi,  some  ex- 
tending nearly  to  the  surface.  These  spaces  contain  protoplasm, 
and  have  become  stained  a  deep  violet  color  by  the  chloride  of 
gold.  Aside  from  these  irregularities  the  lump  seems  to  be 
thoroughly  calcified,  except  in  a  few  spots  upon  the  surface, 

Fig.  135. 


Imperfect  Enamel. 
E,  well-developed  enamel,  transverse  section ;  G,  G,  granular  layer  of  enamel,  with  pear- 
shaped  protoplasmic  enlargements;  7),  dentine,  canaliculi  in  transverse  and  oblique  sections; 
/,  interglobular  spaces.    Magnified  800  diameters. 

which  have  taken  a  slight  violet  stain.  The  exposed  dentine  is 
also  deeply  stained  the  characteristic  violet  color  in  this  locality, 
denoting  insufficiency  of  lime-salts,  or  an  excess,  over  the  ordi- 
nary, of  organic  material. 

"  In  some  instances  the  crown  of  the  tooth  may  be  nearly 
covered  with  a  well-developed  or  a  stratified  and  slightly-pig- 
mented  enamel,  the  other  portions  being  coated  with  a  thin 
layer  highl}"  pigmented,  again  denoting  deficiency  in  lime-salts. 
(See  Fig.  135.) 


FAULTY    DEVELOPMENT.  221 

"  We  present  here  a  transverse  section  of  the  crown  of  a 
molar.  The  thin  and  irregularly-contoured  enamel  exhibits 
only  transverse  sections  of  prisms,  of  a  deep  brown  color.  At  the 
interzonal  layer  numerous  pear-shaped  protoplasmic  spaces  are 
seen  penetrating  the  enamel,  and  in  the  region  nearest  the  den- 
tine the  prisms  appear  as  if  granular  or  sieve-like  (perforated 
with  numerous  small  holes),  indicative  of  a  lack  of  proper  calci- 
fication. 

"  I  will  now  call  attention  to  some  extremely  interesting  and 
instructive  anomalies  in  the  formation  of  this  tissue, — viz,  two 
distinct  varieties  of  enamel,  one  upon  the  other.  First  we  have 
the  anomalous  portion  grafted  or  deposited  upon  a  normal 
enamel,  and  again  anomalous  enamel  first  deposited,  with  the 
peripheral  portion  fairly  normal.     (See  Fig.  136.) 

"  This  represents  a  cusp  of  a  molar,  with  a  conspicuously 
deficient  enamel,  deposited  upon  a  nearly  normal  one.  The 
normal  portion  is  slightly  pigmented,  slightly  stratified,  and 
supplied  with  a  moderate  number  of  granulations,  near  the 
interzonal  layer.  The  outer  or  peripheral  portion  exhibits  a 
layer  which  ends  abruptly  on  one  side,  and  gradually  blends 
with  the  normal  enamel  on  the  other.  This  portion  is  remark- 
ably deficient  in  its  structure.  At  the  boundary-line  between 
the  two  portions  the  enamel-prisms  become  abruptly  devious, 
their  longitudinal  course  being  suddenly  changed  to  a  trans- 
verse one.  In  the  latter  portion  a  few  oblique  sections  are  seen 
alternating  with  the  transverse.  The  whole  portion  superadded 
to  the  normal  is  pierced  by  innumerable  granulations,  which, 
owing  to  their  violet  color,  we  must  conclude  as  protoplasmic 
in  structure,  and,  of  course,  deficient  in  lime-salts.  The  granu- 
lations are,  in  some  places,  arranged  in  rows,  in  others  scattered 
irregularly.  If  a  large  mass  of  enamel  exhibits  prisms  almost 
rectangular  to  their  original  normal  direction,  it  is  not  an  evi- 
dence of  interlacing  of  such  prisms,  but  of  their  unusually 
wavy  courses.  An  originally  deficient  enamel,  upon  which  is 
deposited  a  normal  one,  is  represented  in  Fig.  137. 

"  Here  we  observe  numerous  layers  made  up  of  extremely 
narrow,  interrupted  prisms,  and  at  a  given  line  prisms  of  normal 
width  appear,  first  in  transverse,  then  in  longitudinal  sections. 
This  specimen  affords  a  good  opportunity  to  trace  one  and  the 
same  prism  in  longitudinal,  oblique,  and  transverse  section. 

"  In  all  the  teeth  with  imperfect  enamel  that  I  have  examined. 


222 


THE    ANATOMY    AND    PATHOLOUY    OF    THE    TEETH. 


the  so-called  interglobular  spaces  were  present  in  the  dentine, 
indicating  a  deficient  calcification  of  territories  at  the  period  of 
development  which  corresponds  with  that  of  the  formation  of 
enamel.  In  only  one  specimen  have  I  seen  a  devious  course  of 
the  dentinal  fibers  and  stratification  of  the  dentine. 

Fig.  136. 


Imperfect,  Grafted  upon  Perfect  Enamel. 

D,  dentine  ;  B,  boundary  zone  (interzonal  layer) ;  E,  perfect  enamel :  E^,  imperfect  enamel. 
Magnified  100  diameters. 

"  In  one  instance  peculiar  formations  were  seen  in  the  ce- 
mentum.     (See  Fig.  138.) 

"  The  cementum  here  exhibits  distinct  lamellations  and  scat- 
tered cement-corpuscles,  with  their  longitudinal  diameters  mostly 
arranged  perpendicular  to  the  direction  of  the  lamellte.  The 
cementum  was  abruptly  interrupted  by  the  dipping  downward 


FAULTY    DEVELOPMENT. 


223 


of  the  pericementum  to  the  close  vicmity  of  the  dentine.  In  this 
situation  the  prolongations  of  the  pericementum  were  hardened 
by  globular  depositions  of  lime-salts,  which  were  conspicuous 
by  a  high  degree  of  refraction. 

"  This   anomaly — altogether   different  from    the   process    of 
absorption  of  the  roots  of  temporary  teeth,  or  that  of  bone — 

Fig.  137. 


Perfect,  Grafted  cpox  Imperfect  Examel. 

E'^,  irregular  and  imperfect  layer  of  enamel ;  E-,  regular  layer  of  enamel ;  D,  dentine ;  1, 
interglobular  spaces.    Magnified  500  diameters. 


must  have  occurred  at  the  time  of  the  development  of  the  ce- 
mentum,  which,  as  is  well  known,  takes  place  after  the  forma- 
tion of  the  dentine. 

"A  remarkable  feature  in  connection  with  this  case  was  the 
apparently  perfect  condition,  in  the  mouth,  of  the  gum   and 


224 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


alveolus.  In  the  pericementum  the  microscope  revealed  noth- 
ing anomalous  except  a  few  scattered  calcified  patches.  It  is 
hardlj  possible  that  there  is  any  especial  connection  between 
this  and  the  morbid  process  in  the  enamel,  as  the  enamel  is  com- 
pletely formed  at  a  much  earlier  period  than  this  could  have 
happened.  As  to  the  causes  which  lead  to  the  imperfections  in 
the  enamel  and  other  portions  of  the  teeth  during  the  process 
of  development,  I  will  quote  as  follows  from  an  article  on  '  Den- 
tition and  its  Derangements,'  by  A.  Jacobi,  M.D.,  1862.  He 
says,— 

Fig.  138. 


Irregularities  of  Cementum. 

P,  pericementum ;  C,  stratified  cementum  with  cement-corpuscles  ;  E,  excavations  of 
cementum  filled  with  pericementum;  G,  globular  stratified  depositions  of  lime-salts;  D,  D, 
dentine.    Magnified  100  diameters. 

"  '  The  enamel  of  the  teeth  is  subject  to  several  anomalies.  It 
may  be  either  defective  or  discolored.  Its  defective  formation  ap- 
pears either  in  excavations  dispersed  over  the  surface  of  the  tooth, 
or  there  are  complete  furrows  or  transverse  notches  around  the 
crown  of  the  tooth,  the  body  being  still  covered  with  or  entirely 
deprived  of  enamel.  This  atrophy  is  the  result  of  those  severe 
diseases  which  the  child  may  have  been  suffering  from  during 
the  development  of  the  enamel.     Acute  exanthems  are  said  to 


FAULTY    DEVELOPMENT.  225 

produce  the  dispersed  excavations;  acute  inflammatory  diseases, 
the  furrows;  and  rhachitis  has  often  been  observed  to  be  the 
cause  of  the  entire  absence  of  the  enameL  The  incisors  ot 
rhachitic  children  are  usually  small,  appear  late,  and  are  verj'^ 
liable  to  become  carious.  Acute  exanthems  are  counted  among 
the  causes  of  this  anomaly,  especially  by  such  writers  as  classify 
the  teeth  with  the  dermal  tissue.  Smallpox  is  related  to  produce 
isolated  excavations  which  have  a  great  similarity  to  the  cica- 
trices remaining  after  smallpox.  To  vaccination,  also,  some  have 
attributed  the  defective  development  of  the  enamel.  .  .  . 
The  mucous  membrane  of  the  mouth  is  verj^  irritable,  being 
accustomed  only  to  amniotic  liquor  in  foetal  life,  and  to  milk  in 
the  early  stage  of  extra-uterine  existence.  Every  change  in 
the  diet,  therefore,  the  bad  quality  of  the  material,  or  artifi.cial 
nipples,  the  use  of  candy,  sucking-bags,  or  alcoholic  beverages, 
cofiee,  or  stimulants  of  whatever  kind,  will  act  as  irritants,  pro- 
ducing hyper?emia  or  inflammation  in  a  more  or  less  severe 
form.  ...  A  more  severe  form  is  that  known  by  the  name 
of  aphthous  stomatitis.  The  superficial  layers  of  the  epithelium 
are  not  thrown  otf  during  the  hypersemic  swelling  of  the  mucous 
membrane,  as  in  erythematous  stomatitis,  but  a  real  and  visible 
change  takes  place  in  the  anatomical  structure  of  the  follicles. 
There  is  a  circumscribed,  punctated,  vascular  injection  around 
a  follicle  which  is  gradually  infiltrated  by  exudation.  The  con- 
secutive swelling  increases  in  proportion,  the  follicles  will  burst 
and  exhibit  a  superficial  erosion  or  ulceration,  and  the  adjacent 
mucous  membrane  will  be  sympathetically  aflfected.' 

"  Edmund  Lesser  says,  '  In  the  majority  of  haired  men,  which 
means  congenital  grow^th  of  hair  all  over  the  face  (hirsuties),  I 
hitherto  have  observed  that  defects  or  irregularities  of  the 
dental  system  were  present,  since  not  only  a  number  of  teeth, 
but  the  corresponding  alveoli,  were  missing.  In  some  cases  of 
normal  dentures  a  broadening  of  the  alveolar  processes  was 
apparent.' 

"  Although  of  epithelial  origin,  the  enamel-organ  is  of  a 
myxomatous  structure,  and  thus  represents  a  variety  of  connect- 
ive tissue.  The  history  of  development  of  enamel  (which 
makes  its  appearance  about  the  seventh  month  of  foetal  life)  is 
well  understood,  as  far  as  temporary  teeth  are  concerned,  up  to 
the  time  of  birth  of  the  child.  Still  we  know  nothing  as  to 
the  progress  of  the  lateral  pegs  in  laying  the  foundation  of  the 

16 


226  THE    ANATOMY    AND    PAIHOLOOY    0¥    THE    TEETH. 

enamel-organ  and  the  enamel  of  the  permanent  teeth.  We 
simply  conclude  that  the  process  is  identical  with  that  of  the  tem- 
porary teeth,  in  its  development  during  the  earliest  years  of  extra- 
uterine life.  Since  the  imperfections  of  enamel,  as  described, 
are  observable  upon  permanent  teeth  only,  I,  without  fear  of 
contradiction,  venture  the  hypothesis  that  diseases  of  the  oral 
cavity  only  affecting  the  epithelial  layers,  and  the  pegs  derived 
therefrom,  must  -cause  these  defects.  Such  diseases  occur  in  the 
oral  cavity  of  young  children,  under  the  headings  of  inflamma- 
tion (stomatitis),  from  many  causes,  leading  to  the  formation  of 
blisters,  ulcers,  and  abscesses.  Growth  of  mildew  (so-called 
thrush)  is  known  to  be  a  fertile  source  of  both  such  superficial 
and  deep-seated  disturbances. 

"  Acute  exanthems,  which  sometimes  spread  to  the  mucous 
membrane  of  the  oral  cavity,  undoubtedly  play  an  important 
part  in  causing  inflammation  of  the  enamel-organ,  which  results 
in  producing  defective  enamel. 

"We  can  appreciate  the  probability  that  inflammation  will 
partially  destroy  either  the  original  epithelia  or  the  enamel- 
organ  derived  therefrom,  and  thus  be  the  direct  cause  of  defect- 
ive enamel.  A  simple  obliteration  of  a  number  of  blood- 
vessels which  freely  surround  this  organ  would  suffice  so  to 
interfere  with  its  proper  function  as  to  diminish  the  amount  of 
lime-salts  deposited;  the  enamel-prisms  in  such  case  might 
develop  normally  as  to  size,  but  show  deficiency  in  calcification. 
If,  with  the  inflammation  and  obliteration  of  blood-vessels, 
hemorrhage  takes  place  into  the  enamel-organ,  or  effusion  of 
haemoglobin  should  occur,  pigmentation  of  the  deficiently  calci- 
fied prisms  would  become  intelligible. 

"  We  can  realize  that  the  medullary  tissue  giving  rise  to 
enamel-prisms  will,  in  consequence  of  inflammation,  be  so 
altered  or  misplaced  that  the  outcome  would  be  imperfect,  in- 
complete, or  devious  prisms.  As  I  showed  in  1885  that  the 
formation  of  enamel  takes  place  in  the  shape  of  layers  for  the 
crown  and  layers  for  the  neck,  we  may  grasp  the  possibility  that 
the  earliest  crown-layers  may  be  fully  and  regularly  developed, 
while  the  last  crown-layers  are  interfered  with  and  become 
defective.  Should,  therefore,  an  inflammatory  process  start  at 
the  time  of  the  appearance  of  the  earliest  crown-layers,  and  soon 
abate,  the  enamel  nearest  the  dentine  will  be  found  imperfect. 
If  the  inflammatory  disturbance  continues  for  a  long  period,  the 


DEVELOPMENT   OF    CEMENTUM.  227 

result  will  be  a  thin  and  incompletely  calcified  layer  of  enamel. 
Should  portions  of  the  enamel-organ  be  completely  destroyed 
by  suppuration,  entire  absence  of  enamel  at  such  points  will  be 
the  result.  A  number  of  so-called  miliary  abscesses  in  the 
enamel-organ  will  lead  to  a  porous  or  '  pitted'  enamel.  A 
limited  number  of  somewhat  laro-er  abscesses  would  cause  laro^er 
holes  or  pits,  or  possibly  the  entire  enamel-organ  might  be 
destroyed,  leaving  the  dentine  entirely  unprotected. 

''  In  all  the  cases  of  teeth  with  defective  enamel  that  I  have  ex- 
amined, the  dentine  has  been  found  fully  developed  and  perfectly 
calcified,  with  the  exception  of  quite  numerous  interglobular 
spaces.  These  appear  in  the  dentine  at  the  same  period  ot 
development  during  which  the  enamel-organ  was  ati:ected.  This 
positively  indicates  the  disease  or  diseases  which  caused  the 
production  of  imperfect  enamel  to  have  been  local  rather  than 
general,  as  has  been  supposed  by  some  pathologists.'' 


CHAPTER  XVII. 

DEVELOPMENT  OF  CEMENTUM.* 

Our  researches  into  the  history  of  the  development  of  the 
teeth  extend  over  a  period  of  eight  years,  and  a  large  collection 
of  specimens  has  been  at  our  disposal,  IsTevertheless,  until  re- 
cently, we  hesitated  about  saying  anything  upon  this  topic,  as 
none  of  the  specimens  of  which  we  were  then  possessed  revealed 
anything  of  interest  concerning  the  development  of  cementum. 
This  tissue,  in  human  beings,  is  developed  after  birth,  when  the 
root  and  its  dentine  have  been  fully  formed.  We  know  that 
at  the  time  of  birth  only  the  crowns  of  the  temporary  teeth  are 
present,  but  there  is  no  trace  of  the  roots.  At  what  time  the 
tissue  in  question  begins  to  appear  in  the  human  subject,  we  are 
unable  to  state.  The  only  specimens  at  our  disposal,  in  which 
the  question  of  the  development  of  the  cementum  could  be 
studied,  were  obtained  from  the  lower  jaw  of  a  kitten  about  six 
weeks   old.     As  the    course   of   development  of  dentine   and 

*"  Contributions  to  the  History  of  the  Development  of  the  Teeth,"  by  C. 
Heitzmann  and  C.  F.  W.  Bodecker.      The  Independent  PractHloner,  vols,  viii,  ix. 


228 


THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 


enamel  is  almost  identical  in  cats  and  men,  we  feel  justified  in 
the  assumption  that  the  formation  of  cementum  is  likewise  the 
same  in  both.  "We  are  the  more  confident  because  of  the  knowl- 
edge that  the  development  of  bone  exhibits  the  same  features  in 
cats  as  in  men,  and  because,  as  is  well  known,  cement  is  nothing: 
but  bone-tissue. 


^\G.  139. 

13 

\ 

c 


fcfe)"J>[  ^^/^' 


M 


'\'}'    i\ 


¥^k^ 


UU, 


PO 


\  \ 


^l 


M^&XiKKm 


Apex  of  the  Root  of  a  Tempoeaey  Tooth  of  a  Kittex  Six  "Weeks  Old.    Vertical 

Sectiox. 

Z>,  dentine:  C,  cementum,  in  part  thoroughly  calcified,  and  partly  made  up  of  medullary 
corpuscles:  CB,  basis-substance  of  the  cementum,  composed  of  medullary  corpuscles;  PC,- 
pericementum.    Magnified  200  diameters. 


In  the  above-mentioned  specimens,  taken  from  a  kitten  six 
weeks  old,  we  observed  both  the  temporary  and  permanent 
teeth  in  place.  The  temporary  teeth  were  fully  developed  and 
their  roots  perfect,  whereas  the  permanent  teeth  only  exhibited 
a  small  cap  of  dentine  and  enamel  over  the  papilla,  correspond- 


DEVELOPMENT    OF    CEMENTUM.  229 

ino;  to  a  human  foetus  between  the  seventh  and  eis^hth  months  of 
intra-uterine  life.  Both  the  dentine  of  the  crown  and  that  of 
the  root,  especially  of  the  latter,  were  partly  absorbed,  and  they 
exhibited  bay-like  excavations,  which  were  filled  with  multi- 
nuclear  protoplasmic  masses. 

The  cement  at  the  cervix  of  the  teeth  in  cats  is  a  compara- 
tively narrow  formation,  made  up,  as  in  the  teeth  of  men,  of 
delicate  spindles  arranged  perpendicular  to  the  longitudinal  axis 
of  the  root,  between  which  spindles  we  observe  no  cement-cor- 
puscles. This  layer  is  evidently  developed  from  spindle-shaped 
medullary  corpuscles,  of  which  a  whole  row  is  visible  in  the 
neighboring  pericementum,  A  direct  calcification  of  these 
medullary  corpuscles  leads  to  the  formation  of  the  cementum 
of  the  neck.  Farther  down,  the  cementum  becomes  broader 
by  the  addition  of  a  row  of  medullary  corpuscles  greatly  vary- 
ing in  size,  and  without  distinct  lines  of  demarcation  between 
them.  "With  lower  powers  of  the  microscope  their  protoplasm 
appears  finely  granular ;  with  high  powers,  however,  a  distinct 
reticulum  is  recognizable,  the  same  as  in  all  protoplasmic  for- 
mations. Toward  the  dentine  the  medullary  corpuscles  assume 
■a  high  grade  of  refraction,  indicative  of  a  deposition  of  lime- 
salts,  which  latter  have  been  removed  by  the  treatment  with  the 
ohromic-acid  solution.  The  boundary-line  between  the  dentine 
and  cementum  is  nowhere  distinctly  marked.  Still  farther 
down  toward  the  apex  of  the  tooth  scanty  cement-corpuscles 
make  their  appearance,  invariably  surrounded  by  a  number  of 
finely-granular  medullary  corpuscles,  without  any  marked  terri- 
torial formation  around  each  bone-corpuscle.  IsTearer  to  the 
apex  the  cementum  becomes  very  broad,  exhibiting  a  number 
of  cement-corpuscles.  Here  this  tissue  is  fally  developed  around 
the  dentine,  but  is  yet  in  the  process  of  formation  at  the  periph- 
•ery  of  the  root.  The  latter  portion  plainly  reveals  the  manner 
in  which  the  cementum  is  developed. 

Like  all  the  tissues  of  the  body,  including  the  dentine  and  the 
enamel,  the  cementum  arises  from  medullary  tissue.  In  this 
respect  cementum  and  bone-tissue  show  a  striking  likeness. 
The  medullary  corpuscles  from  which  bone-tissue  arises  bear 
the  name  of  osteoblasts,  and  should  any  one  desire  to  give  a 
special  name  to  the  formers  of  the  cementum,  that  of  cemento- 
blasts  should  be  admissible.  These  corpuscles  become  the  seat 
of  a  deposition  of  lime-salts  before  any  cement-corpuscles  are 


230  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

conspicuous.  We  observed  that  the  previouslj^-calcified  medul- 
lary corpuscles  are  decalcified,  and  after  a  second  calcification 
some  of  them  remained  unchanged,  exhibiting  an  angular  shape 
characteristic  of  bone-  and  cement-corpuscles.  This  stage,  how- 
ever, still  represents  an  incomplete  form  of  cementum.  Lastly', 
another  decalcification  of  the  medullary  corpuscles  takes  place, 
and  this  time  distinct  groups  of  medullary  corpuscles  become 
visible,  the  centers  of  which  are  occupied  b}'  the  cement-corpus- 
cles, and  in  this  manner  the  territories  of  the  cementum  as  well 
as  those  of  bone-tissue  arise.  After  calcification  of  the  medul- 
lary corpuscles  has  been  accomplished,  neither  the  medullary 
corpuscles  nor  the  boundary-lines  of  the  territories  are  conspicu- 
ous; but  when  calcification  is  incomplete,  both  the  medullary 
corpuscles  and  the  territories  are  easily  recognizable. 

With  high  powers  of  the  microscope  we  more  readily  observe 
the  manner  in  which  the  cementum  is  developed.  As  long  as 
this  tissue  is  imperfect,  and  not  fully  calcified,  a  number  of  the 
medullary  corpuscles  assume  a  certain  degree  of  refraction  which 
marks  partial  calcification,  whereas  some  of  the  medullary  cor- 
puscles retain  their  protoplasmic  nature,  and  thus  represent  the 
cement-corpuscles.  Nearer  to  the  dentine  the  medullary  cor- 
puscles are  arranged  in  clusters,  in  the  center  of  which  we 
observe  the  cement-corpuscles.  As  a  rule,  each  cement-corpus- 
cle is  surrounded  by  a  number  of  medullary  corpuscles  repre- 
senting a  territory.  ISTot  infrequently  a  territory  is  indistinctly 
defined.  This  is  the  case  wherever  the  cement-corpuscles  are 
separated  from  each  other  by  a  single  row  of  medullary  corpus- 
cles only,  or  where  the  deposition  of  lime-salts  has  been  com- 
pleted, whereupon  both  the  medullary  corpuscles  and  the 
boundary-lines  of  the  territories  are  lost  to  sight.     (Fig.  140.) 

The  question  arises,  How  are  the  otfshoots  of  the  cement-cor- 
puscles formed  ?  In  order  to  understand  this  process,  we  must 
bear  in  mind  that  the  medullary  corpuscles,  even  when  incom- 
pletely calcified,  exhibit  the  reticular  structure  characteristic  of 
all  protoplasmic  formations.  They  greatly  vary  in  size,  and  are 
separated  from  one  another  by  light  rims,  which  invariabl}' 
appear  traversed  by  delicate  conical  ofifshoots.  It  is  obvious  that 
the  oiFshoots  are  formations  of  living  matter,  serving  for  the 
interconnection  of  all  medullary  corpuscles.  Whenever  lime- 
salts  are  deposited  in  the  meshes  of  the  reticulum  of  the  medul- 
lary corpuscles,  the  interstices  between  them  remain  free  from 


DEVELOPMENT    OF    CEMENTUM. 


231 


MB 


sueli  a  deposit.  The  conical  offshoots  between  the  medullary 
corpuscles  coalesce  at  the  centers  of  the  latter  into  a  filament  of 
living  matter, — the  offshoot  of  the  bone-  or  cement-corpuscle. 
Such  a  delicate  offshoot  remains  interconnected  by  the  lateral 
filaments  running  into  the  reticulum  of  the  medullary  corpus- 
cles, the  same  as  is  the  case  with  dentine-  and  enamel-fibers. 
Even  where  the  calcification  of  the  medullary  corpuscles  has 
assumed   its   highest   degree,    and   where    all    boundary'   lines 

Fig.  140. 


CO 


Cementum  i.v  the  Process  of  FoRM.iiiox  of  a  Temporary  Tooth  of  a  Kitten'  Six 

Weeks  Old. 

J/,  medullary  corpuscles  incompletely  calcified,  but  still  recognizable;  MB,  medullary  cor- 
puscles thoroughly  calcified  in  parts  and  transformed  into  basis-substance  ;  CV,  cement-corpus- 
cles partly  lying  in  a  completely-calcified  basis-substance,  and  partly  occupying  the  centers  of 
groups  of  medullary  corpuscles,  the  so-called  territories ;  B,  basis-substance.  Magnified  1200 
diameters. 


between  them  have  disappeared,  the  reticulum  in  the  basis- 
substance  remains  unaltered,  and  plainly  visible  with  a  good 
immersion  lens,  without  the  addition  of  any  reagent. 

The  results  of  our  researches  concerning  the  history  of 
development  of  the  cementum  of  the  temporary  teeth  of  a 
kitten  six  weeks  old  are  as  follows : 

I.  The  cementum  arises  from  medullary  tissue,  the  same  as 
bone-  and  all  other  tissues  of  the  bodv. 


232  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

II.  The  medullary  corpuscles  first  become  the  seat  of  a  deposi- 
tion of  lime-salts  before  any  cement-corpuscles  are  visible. 

III.  The  lime-salts  are  dissolved  and  redeposited  again  in  the 
medullary  corpuscles,  which  are  arranged  irregularly  around 
the  cement-corpuscles,  the  latter,  however,  remaining  free  from 
calcareous  infiltration. 

IV.  Still  later  the  medullary  corpuscles  are  arranged  in 
groups,  the  centers  of  which  are  the  cement-corpuscles,  the  sum 
total  furnishing  the  territories  around  the  cement-corpuscles. 

Y.  The  offshoots  of  the  cement-corpuscles  are  filaments  of 
livino-  matter,  orio-inatino;  from  the  briclo:es  traversing  the  inter- 
stices  between  the  medullar}'  corpuscles. 

VI.  The  reticular  structure  of  the  original  medullary  corpus- 
cles is  preserved  in  the  basis-substance  even  after  the  completion 
of  the  calcification  of  the  latter,  and  the  disappearance  of  the 
original  medullary  corpascles. 

The  development  of  the  roots  of  the  temporary  as  well  as  the 
permanent  teeth  has  been  carefully  studied,  as  far  as  naked-eye 
appearance  goes,  by  C.  i^.  Peirce.  The  illustrations  published 
by  him  I  have  copied  in  the  chapter  on  "  Faulty  Development," 
Fig.  120,  page  196.  My  rather  limited  knowledge  of  this  topic 
will  excuse  mv  reference  to  an  author  known  to  be  reliable. 


CHAPTER   XVIII. 

THE  DEVELOPMENT  OF  TEETH  IN  EMBRYOS   AFFECTED  WITH 
EHACHITIS.* 

Amono  the  numerous  embryos  whose  teeth  the  writers  have 
examined,  there  were  three  aftected  with  so-called  congenital 
rhachitis.  One  of  these  was  a  seven-months"  foetus,  another 
seven  months  and  a  half,  while  the  third  was  eight  months  old. 
Macroscopically  the  two  former  did  not  exhibit  any  symptoms 
of  rhachitis,  and  it  was  only  upon  microscopical  examination  of 
the  jaw-bones  that  we  were  enabled  to  recognize  the  morbid 
process,  whose  characteristic  feature  is  a  new  formation  of  hya- 

*  "  Contributions  to  the  History  of  Development  of  the  Teeth, "'  by  Carl  Heitz- 
mann  and  C.  F.  TT.  Bodecker.     Indepenrlent  Practitioner^  vols,  viii  and  ix. 


DEVELOPMENT    OF    RHACIIITIC    TEETH    IX    EMBRYOS.  233 

line  cartilage  in  the  place  of  bone-tissue.  The  trabecular  of  the 
cancellous  bone-tissue  were  scantier,  and  the  lione-corpuscles 
within  them  were  much  larger,  than  those  iu  normal  bone-tissue. 
In  many  places,  however,  hyaline  cartilage  was  present  instead 
-of  bony  trabeculte,  and  in  the  medullary  spaces  between  them. 
The  cartilage-corpuscles  often  were  of  a  brown  color,  caused 
either  by  previous  hemorrhage  or  by  a  new  formation  of  blood- 
corpuscles  and  haemoglobin.  The  third  foetus,  which  was  eight 
months  old,  showed  the  symptoms  of  congenital  rhachitis  in 
such  a  degree  that  all  l»one-tissue  throughout  the  l;>ody  was 
lacking,  and  only  in  the  lower  jaw  were  found  a  few  trabeculEe. 
This  foE-tus  was  delivered  l)y  a  healthy  woman,  who,  during  her 
pregnancy,  for  a  nural»er  of  months  furnished  dogs,  cats,  and 
rabbits  with  soup,  meat,  bread,  and  vegetables,  mixed  respect- 
ively ^^ith  lactic  acid,  for  the  purpose  of  artificially  producing 
rhachitis  and  osteomalacia  in  these  animals.  These  experiments 
were  made  by  Carl  Heitzraann  (see  ''  Microscopical  Morphol- 
ogy," 1888)  and  proved  to  be  successful.  Dogs  and  cats,  treated 
with  lactic  acid  soon  after  birth,  became  rhachitic,  and  treated 
with  lactic  acid  for  several  months  in  succession,  l)ecame  affected 
with  osteomalacia. 

The  woman  who  gave  l;»irth  to  this  ftjetus  was  healthy  during 
pregnancy,  and  remained  so  after  delivery.  The  f*  etus,  on  the 
contrary,  died  shortly  after  Ijirth,  from  intracranial  hemorrhage 
caused  by  pressure  during  labor,  on  account  of  the  complete 
absence  of  cranial  bones. 

The  abnormal  occurrences  in  the  teeth  of  these  three  rhachitic 
embryos  were  so  striking  and  so  numerous  that  we  made  an 
attempt  to  arrange  them  under  a  number  of  headings,  being 
aware  of  the  fact  that  diiferent  chronic  ailments  both  of  a 
mother  and  of  a  foetus,  more  especially  rhachitis  of  the  foetus, 
reflect  on  the  growth  of  the  teeth,  and  leave  marks  in  the  shape 
of  transverse  grooves  or  furrows  upon  them. 

I.  Premature  Eruption  of  Ill-developed  Teeth,  found  in  the 
lower  jaw  of  a  rhachitic  fptus.  seven  mimths  old.  (See  Fig. 
141.) 

This  tooth  had  reached  a  stage  of  development  corresponding 
to  about  the  seventh  month  of  intra-uterine  life,  but  had  grown 
above  the  level  of  the  gum,  and  was  plainly  visible  to  the  naked 
eye.  This  specimen  helped  to  settle  a  mooted  question  con- 
cerning the  origin  of  Xasmvth's  membrane, — the  c-uticle  of  the 


234 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


tooth.  The  writers  observed  that  the  flat  epithelial  layer  cov- 
ering the  summit,  and  the  dentine  at  the  deeper  portion  of  the 
tooth,  is  a  direct  reduplication  of  the  flat  epithelial  layer  of  the 
gum.     The  papilla  is  moderately  supplied  with  blood-vessels. 


Fk     141 


Premature  Eruption  of  a  Lower  Incisor  of  a  Ehachitic  Fcetus,  SevenIMoxths 

Ol.D. 

G,  gum ;    G,  fibrous  connective  tissue ;    EO,  myxomatous    enamel-organ.     Magnified  '50 
diameters. 

and  is  of  a  markedly  myxomatous  structure,  especially  at  its 
lower  part,  which  appears  lobulated.  It  is  bordered  by  a 
structureless  layer  at  its  lower  portion,  which  we  consider  a 
normal  feature,  and  w^hich  is  always  present  previous  to  the 


DEVELOPMENT    OF    RHACHITIC    TEETH    IN    EMBRYOS.  235 

appearance  of  odontoblasts.  The  gum  is  composed  of  a  loose, 
delicate,  fibrous  connective  tissue.  At  the  right  side  of  the 
specimen,  near  tlie  lower  portion  of  tlie  papilla,  there  appears 
an  isolated  layer  of  invxomatous  tissue,  which  extends  below 
the  papilla,  bearing  the  characteristics  of  the  enamel-organ.  Its 
outer  periphery  shows  a  number  of  buds  or  nests,  which  are  the 
offspring  of  the  external  epithelium. 

II.  Double  Papillae. — In  the  same  foetus  the  writers  observed 
two  papillae  of  lower  bicuspids,  which  at  their  bases  were  united 
into  one  continuous  l>road  mass,  whereas  higher  up  there  was 
seen  a  cancellous  bony  structure,  separating  the  papillae,  which 
proves  that  they  belonged  to  two  separate  teeth.  The  struc- 
ture of  these  papillae  was  markedly  myxomatous,  similar  in 
appearance  to  that  of  the  papillae  of  pig's  teeth.  The  enamel- 
organ  appeared  to  be  in  full  development,  being  lined  by  the 
internal  epithelium,  which  was  broken  up  into  medullary  tissue, 
and  an  external  epithelium  broken  up  into  epithelial  nests. 
Along  the  internal  epithelium  peculiar  folds  and  indentations 
are  visible,  which  the  writers  propose  to  describe  later  on.  iSTo 
trace  of  dentine  or  enamel  was  visible  upon  these  germs. 

III.  Dwarf  Teeth. — In  the  rhachitic  foetus  which  was  seven 
and  a  half  months  old,  the  writers  met  with  minute  teeth  which 
were  in  a  stage  of  development  corresponding  to  the  age  of  the 
foetus.     (See  Fig.  142.) 

The  papillae  are  of  very  irregular  shape,  being  partly  blunt, 
partly  elongated,  and  sharply  marked  by  a  constriction  at  the 
place  corresponding  to  the  neck  of  the  future  tooth.  Above 
the  neck  the  papillae  are  of  the  usual  lancet  or  myrtle-leaf  shape, 
exhibitino;  alonsr  their  borders  either  odontoblasts  or  rows  of 
medullary  corpuscles,  and  showing  comparatively  few  blood- 
vessels. The  dentine  is  curved  around  the  constriction  in  a 
marked  degree,  surrounding  the  neck  of  the  tooth  like  a  cap. 
Its  canaliculi  are  wide,  but  without  pathological  features.  The 
enamel  is  likewise  to  be  considered  normal,  but  the  enamel- 
organ  is  missing  in  all  of  these  specimens,  which  indicates  that 
the  myxomatous  reticulum  was  exhausted.  The  external  epi- 
thelium only  shows  its  presence  by  small  epithelial  nests  and 
buds  along  the  already-formed  enamel. 

A  peculiar  feature  of  both  the  papilla  and  the  surrounding 
connective  tissue  is  the  presence  of  rusty-brown,  needle-shaped 
crystals  of  haematoidin,  sometimes  clustered  together  in  numer- 


236 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


oa3  masse?.  These  are  the  result  of  a  previous  hemorrhage, 
although  it  is  not  expHcable  how  they  appear  in  the  papilla, 
where  the  blood-vessels  are  extremely  scanty  and  just  in  the 
process  of  formation. 

IV,  Malformations  and  Malpositions  of  the  Enamel-Organ. 
— In  the  teeth  of  a  rhachitic  foetus  we  not  infrequently  meet 
with  enamel-organs  markedly  differing  from  normal  ones,  the 
difference  mainly  consisting  in  the  lack  of  a  myxomatous 
reticulum.     This  tissue  appears  in  the  shape  of  small,  glistening 

Tig.  142. 


D^TARFED  Teeth  of  a  Ehathitic  Fcetus,  Seyex  and  a  Half  Months  Old. 

A,  blunt  foot-shaped  papilla,  with  a  constriction,  from  which  the  dentine  starts;  i?,  elon- 
gated narrow  papilla,  from  which  grows  at  an  acute  angle  the  tooth,  again  marked  by  a  con- 
stricted neck.    Magnified  50  diameters. 


granules,  arranged  either  in  the  shape  of  clusters  or  of  an  indis- 
tinct reticulum.  The  granules  themselves  vary  somewhat  in 
size,  and  among  them  larger  granular  corpuscles  may  be  seen, 
which,  without  any  regular  arrangement,  are  yet  entitled  to  the 
name  of  nuclei.  The  meshes  of  this  irregular  reticulum  hold 
an  apparently  structureless  mucoid  basis-substance.  Besides 
these  irregular  formations  of  the  enamel-organ,  we  sometimes 
meet  with  malpositions  of  it,  either  in  a  normal  or  an  anomalous 
condition.     (See  Fig.  143.) 


DEVELOPMENT  OF  RHACHITIC  TEETH  IX  EMBRYOS. 


237 


In  this  specimen  the  enamel-organ  is  located  entirely  above  a 
tooth,  which  is  likewise  anomalous.  It  is  widened  in  a  horizontal 
direction,  nearl}^  parallel  to  the  outer  surface  of  the  mucosa.    It 


Fig.  143. 


Anomalous  Location  and  Foematiox  of  the  Examel-Oegan  of  a  Human  Fcetus  Seven 
AND  A  Half  Months  Old,  affected  -n-iTH  Congenital  Rhachitis. 

EO,  enamel -organ  ;  EE,  external  epithelium;  E,  enamel;  D,  dentine;  P,  papilla.    Magni- 
fied 100  diameters. 


extends  downward  along  the  newly-formed  dentine  and  along 
the  upper  portion  of  the  papilla.  It  is  lined  with  medullary 
tissue  and  with  clusters  of  epithelia,  both  being  derived  from 
the  external  epithelium,  whereas  the  internal  epithelium  is  com- 


238  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

pletely  exhausted  for  the  formation  of  the  enamel.  The  layer 
of  medullary  tissue  arising  from  the  external  epithelium  is 
broad,  but  short  on  one  side,  and  narrow  and  much  elongated 
on  the  other  side  of  the  enamel-organ.  The  tooth  is  anomalous 
not  in  its  size,  nor  in  respect  to  the  stage  of  development  it  is 
in,  but  on  account  of  its  devious  papilla,  resembling  the  teeth 
illustrated  in  Fig.  142.  The  specimen  was  obtained  from  the 
same  embryo  as  those  illustrated  in  Fig.  142.  The  papilla  is 
constricted  at  the  place  where  the  dentine  begins,  at  the  neck 
of  the  tooth,  below  which  the. papilla  suddenly  widens  and  pro- 
duces a  bluntly-elongated  body  of  considerable  size,  composed 
of  medullary  tissue,  and  holding  a  number  of  clusters  of  hsema- 
toidin  crystals,  which  are  also  seen  in  the  neighboring  fibrous 
connective  tissue.  Another  misplacement  of  the  enamel-organ 
is  illustrated  in  Fig.  141,  in  which  it  is  depicted  as  located 
beneath  the  base  of  the  papilla. 

V.  Folds,  Convolutions,  and  Reduplications  of  the  Epithelium 
of  the  Enamel-Organ. — In  both  rhachitic  embryos  from  which 
specimens  have  been  taken,  we  have  encountered  in  the  enamel- 
organ  peculiar  formations,  which  we  propose  to  describe  under 
the  above  heading.  JSTear  the  external  epithelium,  which  at  the 
age  designated  is  invariably  split  up,  we  have  sometimes  found 
concentrically-arranged  epithelial  nests,  or  clusters  of  medullary 
tissue,  imbedded  in  an  otherwise  normal  myxomatous  reticulum. 
Far  more  common  than  these  formations,  which  depend  upon  a 
reduplication  of  the  external  epithelium,  are  foldings  and  con- 
volutions of  the  internal  epithelium.     (See  Fig.  144.) 

The  internal  epithelium  shows,  sometimes,  simple  indenta- 
tions, which  are  also  observed  occasionally  in  normal  teeth  of 
the  same  stage  of  development.  At  other  times  there  is  a 
series  of  successive  convolutions  of  the  internal  epithelium. 
IS'eighboring  this  epithelium  the  myxomatous  tissue  of  the 
enamel-organ,  as  a  rule,  is  in  a  medullary  condition,  with  and 
without  a  pronounced  intermediate  layer.  Obviously,  such 
sinuosities  correspond  to  furrows  of  the  enamel-organ,  and  very 
probably  may  cause  the  ridges  and  furrows  often  observed  upon 
this  tissue.  The  highest  degree  of  reduplication  of  the  internal 
epithelium  is  sometimes  seen,  together  with  apparently  isolated 
buds  of  dentine,  surrounded  by  and  inclosed  in  a  layer  of  amelo- 
blasts  and  myxomatous  tissue.  The  dentine  consists  either  of  a 
narrow  calcareous  rim,  or  a  cap  in  which  we  may  observe  dis- 


DEVELOPMENT    OF    RHACHITIC    TEETH    IX    EMBRYOS. 


239 


tinct  dentinal  canaliculi.  If  the  dentinal  cap  appears  as  a  thin 
calcified  ledge,  it  is  composed  of  calcified  medullary  corpuscles, 
beneath  which  odontoblasts  are  perceptible.  If  the  ledge  of 
the  dentine  is  broader  and  supplied  with  dentinal  canaliculi,  we 
notice  close  beneath  it  a  layer  of  medullary  corpuscles  followed 
by  a  layer  of  odontoblasts  which  are  usually  in  process  of  break- 


FiG.  144. 


Reduplication  of  the  Inteexal  Epithelium  of  a  Rhachitic  Fcetus  Sevex  and   a 
Half  Months  Old,  around  a  Bud  of  Dentine. 

^(9,  myxomatous  enamel-organ;  -E^,  external  epithelium  ;  A.layer  of  ameloblasts;  /X,  in- 
terstitial layer  composed  of  spindle-shaped  elements  surrounding  the  ameloblasts  ;  A^,  A^,  layer 
of  ameloblasts  toward  an  already-formed  enamel ;  M,  myxomatous  tissue  approaching  the 
structure  of  medullary  tissue  ;  D,  dentine  with  underlying  odontoblasts.  Magnified  200  diam- 
eters. 

ing  up  into  medullary  corpuscles.  It  may  be  possible  that  such 
formations  are  the  starting  points  of  the  transverse  furrows  ob- 
served upon  the  labial  surfaces  of  the  temporary  teeth  of  rickety 
children,  although  these  occurrences  are  far  more  common  on 
permanent  teeth. 
VI.  Anomalies  of  Enamel. — It  is  a  common  feature  in  teeth 


240 


THE    ANATOMY    AND    PATHOLOGY    OF   THE    TEETH. 


of  rhacliitic  children  that  the  interstices  between  the  enamel- 
prisms  are  wide,  and  their  tenants,  the  enamel-libers,  are  very 
distinct,  often  running  a  wavy  course  independent  of  the  con- 
tours of  the  enamel-prisms.  The  prisms  themselves  are  finely 
granular,  without  distinct  cross-lines.  These  features  are  ex- 
plained by  the  evidence  of  a  deficient  calcification  of  the  enamel^ 


Anomalous  ExAMf:L  or  a  Rhachitic  F(etus  Seven  and  a  Half  Months  Old. 

EE,  enamel-organ  of  medullary  character  arisen  from  the  external  epithelium  ;  E,  enamel 
composed  of  prisms  of  a  markedly  wavy  course  ;  M,  cluster  of  medullary  corpuscles,— {.c,  non- 
calcified  enamel-tissue  ;  IL,  interzonal  layer  filled  with  medullary  corpuscles ;  D,  dentine. 
Magnified  500  diameters.  • 

which  allows  the  cutting  of  thin  sections  of  the  enamel  after  it 
has  been  softened  in  chromic-acid  solution,  whereas  it  is  impos- 
sible to  obtain  sections  of  normal  enamel  in  the  same  manner. 
In  a  rhachitic  foetus  eight  months  old,  we  have  observed  in  the 
enamel  dark-brown  colorations,  which  are  to  be  considered  as 


DEVELOPMENT    OF    KHACHITIC    TEETH    IX    EMBRYOS.  241 

pigmentations  of  the  enamel-rods.  Another  feature  in  the 
■enamel  of  rhachitic  embryos  is  a  markedly  wavy  course  taken 
by  the  enamel-prisms, — so  much  so  that  in  a  strictly  longitudinal 
section  alternate  layers  of  enamel-prisms  appear,  some  of  which 
are  cut  longitudinally,  while  others  are  transverse.  (See  Fig. 
145.) 

Frank  Abbott  has  already  drawn  attention  to  the  fact  that 
transverse  sections  of  enamel-prisms,  alternating  with  longitu- 
dinal sections,  are  not  caused  by  an  interlacing  of  the  enamel- 
prisms,  but  by  a  wavy  or  devious  course  of  the  enamel-prisms 
themselves,  and  our  specimens  have  furnished  satisfactory  proof 
of  the  correctness  of  the  latter  view. 

jSTot  infrequently  we  observe  at  the  summit  of  the  dentine,  in 
the  interzonal  layer,  medullary  corpuscles,  either  arranged  in 
rows  or  irregularly  scattered  in  the  vicinity  of  the  dentine.  Such 
formations  scarcely  admit  of  any  other  interpretation  than  that 
the  medullary  elements,  from  which  the  enamel-prisms  originate, 
have  not  been  calcified,  but  have  remained  in  an  embryonal 
state.     (See  Fig.  145,  M  and  IL.) 

In  specimens  from-  a  rhachitic  foetus  seven  and  a  half  months 
old,  the  enamel  appeared  bordered  by  a  medullary  tissue,  whose 
orio;in  could  be  directlv  traced  from  the  buds  and  clusters,  the 
remains  of  the  external  epithelium.  Here,  therefore,  our  pre- 
vious assumption,  that  the  external  epithelium  likewise  furnishes 
material  for  the  increase  of  the  enamel,  can  be  directly  proven. 

VII.  Anomalies  of  the  Dentine. — The  dentine  of  all  rhachitic 
teeth  is  conspicuous  by  wide  dentinal  canaliculi,  in  which  the  den- 
tinal fibers  and  their  lateral  offshoots  are  easily  discernible.  The 
basis-substance  shows  a  more  or  less  marked  reticular  structure, 
without  the  application  of  any  reagent.  In  a  foetus  eight  months 
old  we  found  peculiar  formations  of  dentine,  which  evidently 
are  caused  by  a  deficient  calcification  of  this  tissue.  (See  Fig. 
146.) 

Such  spaces  send  offshoots  upward  and  downward  in  the  den- 
tine, which  represent  either  conicall^'-widened  dentinal  canals, 
or  broad  routes  replacing  the  same.  The  spaces  and  their  larger 
branches  are  filled  with  medullary  corpuscles  in  all  stages  of 
development.  Where  the  space  inosculates  with  dentinal 
canaliculi,  the  tenants  of  the  latter  are  coarse  fibrillas,  with 
spindle-shaped  widenings  composed  of  large  granules.  Both 
within  these  spaces  and  in  their  vicinity  we  observe 'globular 

17 


242 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


formations  which  exhibit  the  features  of  badlj-developed 
secondary  dentine,  or  globular  dentine,  resembling  the  structure 
of  the  dentine  of  the  so-called  pulp-stones,  or  denticles.     Spaces 


Fig.   146. 


Medullary  Space  and  Globular  Mass  in  the  Dentine  of  a  Tooth  of  a  Rhachitio 
FcETUs  Eight  Months  Old. 

M,  medullary  corpuscles  filling  a  crescentic  space  in  the  dentine  ;  B,  branch  of  the  creseentic 
space  replacing  a  dentinal  canaliculus ;  G,  globular,  concentrically-striated  mass.  Magnified 
600  diameters. 

of  this  description  resemble  the  interglobular  spaces  of  Czermak, 
but  thev  are  more  irregular  and  much  larger. 

VIII.  Anomalies  of  the  Papilla. — The  writers  have  described 
and  illustrated,  in  Fig.  142,  anomalous  papillse  of  peculiar  shapes. 
In  such  papillfe  we  often  observe  crystals  of  heematoidin 
grouped  together  in  clusters,  the  origin  of  which  must  be  sought 
for  in  an  imbibition  by  the  tissue  of  the  coloring-matter  of  the 
blood  at  a  very  early  stage  of  development.  The  writers 
furthermore  wish  to  draw  attention  to  peculiar  formations  met 
with  in  the  medullary  tissue  of  the  papilla. .    (See  Fig.  147.) 

Such  globules  we  have  observed  only  at  the  summit  of  the 


DEVELOPMENT    OF    RIIACHITIC    TEETH    IN    EMBRYOS. 


243 


papilla,  and  in  close  connection  with  medullated  nerve-fibers. 
The  globules  are  pale,  finely  granular,  and  with  either  smooth 
or  lobulated  contours.  Their  interior  shows  faint  marks  of 
division,  which  indicate  that  the  globules  have  arisen  from 
medullary  corpuscles  or  clusters  thereof.  We  are  unable  to  de- 
termine the  nature  of  such  corpuscles,  which  seem  to  be  in 
relation  to  newly-forming  medullated  nerves.     All  the  nerve- 


FiG.   147. 


Globules  in  the  Papilla  in  a  Rhachitic  Fcettjs  Seyen"  and  a  Half  Months  Old. 

G,  G,  granular  globules,  partly  smooth,  partly  lobulated;  iV,  iV,  medullated  nerves.  Magni- 
fied 600  diameters. 


fibers  seem,  however,  to  run  between  the  globules,  although  it 
appears  in  the  drawing  as  if  a  bundle  of  nerves  inosculated  with 
a  globule.  This  may  be  explained  by  the  assumption  of  a  de- 
vious course  of  the  nerve-bundle. 

The  most  interesting  feature  of  such  papillae  is  that  the  medul- 
lated nerves  first  appear  at  the  summit  of  the  papilla,  ^whereas 
the  lower  portions  of  the  papillae  are  free  from  nerves,  and  only 


244  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

exhibit  scanty  capillary  blood-vessels.  The  nerves  still  appear 
to  be  composed  of  rows  of  medullated  corpuscles,  without  any 
trace  of  the  niyelin  sheath.  Whether  or  not  axis-cylinders  are 
present,  we  could  not  determine  from  the  longitudinal  sections 
before  us.  This  much  is  certain, — that  the  nerves  grew  inde- 
pendent of  the  central  nervous  sj'stem  ;  that  they  were  in  no 
connection  with  alreadj'-formed  nerves  of  the  central  nervous 
system,  and,  therefore,  that  they  must  have  arisen  from  medul- 
lary corpuscles  in  essentially  the  same  manner  as  other  tissues. 
Those  who  strictly  adhere  to  the  doctrine  of  exclusiveness  in 
embryology — the  doctrine  that  development  proceeds  from  the 
three  original  layers — will  try  in  vain  to  explain  such  an  inde- 
pendent formation  of  nerves  in  the  middle  of  connective  tissue. 


CHAPTER   XIX. 

THE  DENTAL  PULP.* 


Methods. — The  best  method  of  preparing  pulp-tissue  for  ex- 
amination is  to  place  the  tooth,  immediately  after  its  removal 
from  the  mouth,  in  an  aqueous  solution  of  chromic  acid  of  from 
one-half  to  one  per  cent,  strength.  To  this  mixture  may  be 
added,  every  third  or  fourth  day,  one  or  two  drops  of  dilute 
hydrochloric  acid,  to  hasten  the  process  of  decalcification.  It  is 
important  to  use  a  large  quantity  of  the  liquid, — not  less  than  a 
quart  for  one  tooth  or  a  few, — and  to  renew  the  same  at  least 
every  second  or  third  day.  After  the  teeth  have  been  in  the 
chromic-acid  solution  a  few  weeks,  the  peripheral  portion  of  the 
dentine  will  become  sufficiently  soft  to  be  cut  by  a  razor.  When 
the  hard  parts  of  the  dentine  are  reached  by  the  cutting-instru- 
ment, the  extraction  of  the  lime-salts  must  again  be  continued 
in  the  manner  described  above,  until  the  pulp- cavity  is  reached. 

Another  method  is  to  split  the  tooth,  as  soon  as  possible  after 
its  extraction  from  the  mouth,  with  a  strong  pair  of  excising- 
forceps.  The  teeth  best  adapted  for  this  method  are  the  incisors, 
cuspids,  and  bicuspids.     By  an  experienced  manipulator  the 

*  ' '  The  Minute  Anatomy,  Physiology,  Pathology,   and  Therapeutics  of  the 

Dental  Pulp."    Dental  Cosmos,  1882. 


THE  den;tal  pulp.  245 

pulps  of  molars  can  be  extricated  from  their  inclosing  walls,  but 
with  less  success  than  in  the  teeth  before  mentioned.  In  split- 
ting, put  the  cutting-edges  of  a  sharp  pair  of  excising-forceps  in 
the  longitudinal  direction  near  the  apex  of  a  single-rooted 
tooth,  then  exert  a  sharp  and  quick  pressure,  when,  as  a  rule, 
the  tooth  will  split  into  halves  with  the  pulp-cavity  exposed. 
Immediately  moisten  the  pulp  with  a  solution  of  chloride  of 
sodium  in  water,  of  the  strength  of  about  one-half  of  one  per 
cent,,  and  then  remove  the  pulp.  The  greatest  care  must  be 
taken,  in  picking  the  fragments  of  the  tooth  from  the  pulp-tissue, 
to  avoid  tearing  the  organ,  as  tearing  greatly  alters  the  micro- 
scopical aspect  of  nerve-tissue.  If  the  pulp  is  to  be  stained  with 
carmin,li8ematoxylon,fuchsin,hyperosmic  acid,  picro-indigo,  or 
chloride  of  gold,  etc.,  place  it  in  the  staining-fluid  immediately 
after  its  removal  from  the  hard  parts  of  the  tooth. 

Among  the  reagents  mentioned,  I  have  found  but  one  of  con- 
siderable value, — viz,  the  solution  of  chloride  of  gold  of  the 
strength  of  one-half  of  one  per  cent.  This  reagent  may  be 
applied  to  fresh  pulps  as  well  as  to  very  thin  sections  obtained 
after  hardening  in  chromic  acid.  These  specimens,  however, 
must,  as  a  matter  of  course,  be  carefully  washed  with  distilled 
water  before  the  chloride-of-gold  solution  is  added.  The  re- 
agent may  be  allowed  to  remain  in  contact  with  the  specimens 
for  from  twenty  to  thirty  minutes,  when  they  should  again  be 
washed  in  distilled  water  and  exposed  to  daylight.  In  a  few 
days  fresh  specimens  assume  a  bright  violet  color,  while  sections 
which  have  previously  been  in  a  chromic-acid  solution  become 
brownish-violet.  Osmic  acid,  in  solution,  one  per  cent,  strong, 
renders  the  contours  of  the  constituent  tissues,  and  especially 
those  of  the  medullated  nerve-fibers,  more  distinct,  as  it  stains 
the  nerve-fat  dark  green.  Both  fresh  and  chromic-acid  speci- 
mens may  be  treated  with  osmic  acid.  Thin  sections  do  not 
require  more  than  an  hour's  exposure  to  this  reagent,  while 
whole  fresh  pulps  may  be  left  in  it  for  two  or  three  hours.  Ex- 
cept the  ammoniacal  solution  of  carmin,  which  is  known  to  be 
excellent  for  staining  certain  parts  of  the  tissue,  I  would  not 
lay  stress  upon  applying  any  of  the  other  reagents  mentioned. 

If  we  wish  to  examine  the  pulp,  together  with  the  inclosing 
dentine,  or  a  pulp-stone,  the  specimen,  previously  softened  by 
chromic  acid,  must  be  imbedded  in  a  mixture  of  paraffin  and 
wax,  which  is  best  done  in  the  following  manner.     Place  the 


246  THE    ANATOMY'    AND    PATHOLOGY    OF    THE    TEETH. 

softened  tooth  in  absolute  alcohol  for  about  twenty-four  hours ; 
then,  of  rather  thick  paper,  prepare  a  box  somewhat  larger  than 
the  specimen ;  warm  the  imbedding  mixture,  which  consists  of 
about  eight  parts  of  paraffin  and  one  of  white  wax,  until  it  is 
barely  liquid ;  pour  enough  of  it  into  the  paper  box  about  to 
half-fill  it:  then  take  the  specimen  out  of  the  alcohol,  and  as 
soon  as  it  begins  to  dry,  place  it  in  the  paper  box  and  pour  over 
it  some  more  of  the  paraffin  and  wax,  so  as  to  cover  it  com- 
pletely. Care  must  be  taken  not  to  have  the  imbedding  mixture 
too  hot,  as  it  may  injure  the  specimen.  The  latter,  after  the 
mixture  has  become  sufficiently  hard,  is  ready  for  cutting,  when 
very  thin  sections  can  easily  be  obtained.  To-da}^  imbedding  in 
celloidin  is  used  almost  exclusively. 

If  a  fresh  pulp  is  thin  enough,  it  may,  immediately  after  its 
removal  from  the  split  tooth,  be  transferred  to  the  slide,  with 
the  addition  of  an  indifferent  fluid,  such  as  the  solution  of  chlo- 
ride of  sodium,  etc.  But  a  slight  and  careful  pressure  upon  the 
cover  is  necessary  in  order  to  spread  fresh  specimens.  The 
fresh  pulps  of  lower  incisors,  being  the  thinnest,  are  the  best 
adapted  for  examining  the  system  of  blood-vessels.  In  a  short 
time,  however,  they  fade  away,  and  the  specimen  becomes  unfit 
for  preservation.  Isolated  pulps  may  be  placed  between  two 
plates  of  velvet  cork,  and  thus  cut  into  thin  sections  with  the 
razor.  I  would  recommend  chemically-pure  glycerin  as  the  best 
preserving-fluid  for  pulp-specimens. 

The  Minute  Structure  of  Pulp -Tissue. — The  dental  pulp  repre- 
sents the  remains  of  the  former  dentine  papilla,  and  occupies  the 
central  cavity  of  the  tooth.  It  is  richly  supplied  with  blood- 
vessels and  nerves,  which  enter  the  pulp-chamber  at  the  apex  of 
every  root  through  one  or  more  openings.  The  tooth  for  its 
supply  of  nourishing  material  depends  upon  the  pulp  and  the 
pericementum.  In  many  instances  a  tooth,  after  the  death  of 
the  pulp,  may  be  retained  in  its  place  for  years,  deriving  its 
blood-supply  from  the  pericementum  only. 

If  we  exaiTiine  a  thin  longitudinal  or  transverse  section  of  the 
pulp  with  low  powers  of  the  microscope  (200  diameters),  we 
recognize  a  large  number  of  blood-vessels  and  bundles  of  medul- 
lated  nerve-fibers.  The  majority  of  these  blood-vessels  are 
capillaries;  the  veins  are  less  numerous,  and  arteries  are  scarce. 
Often  we  find  in  a  pulp  only  one  arteriole.;  frequently  arterioles 
lie  in  the  midst  of  the  medullated  nerve-bundles.     The  medul- 


THE    DENTAL    PULP. 


247 


lated  nerve-bundles  mostly  run  in  a  longitudinal  direction,  but 
not  in  frequently  ^we  observe  smaller  bundles,  or  single  medul- 
lated  nerve-fibers,  to  diverge  from  tlie  longitudinal  direction, 
and  to  run  obliquely  tbrough  the  pulp-tissue. 

In  transverse  sections  of  the  pulp  we  meet  witli  arteries,  veins, 


Normal  Pulp  ix  Transverse  Section,  Stained  with  Chloride  of  Gold.    From  a 
Molar  of  a  Youth  Sixteen  Years  Old. 

0,  layer  of  odontoblasts,  arranged  in  rows  of  medullary  corpuscles;  B,  granular  layer;  M,  M, 
myxomatous,  erroneously  termed  "adenoid,"  tissue;  C,  C,  capillary  and  venous  blood-vessels; 
T,  r,  bundles  of  medullated  nerves  in  cross-section;  i,  i,  bundles^of  medullated  nerves  in 
longitudinal  section.    Magnified  75  diameters. 


and  capillaries,  the  first  cut  across,  the  others  distributed  in  all 
directions.  The  bundles  of  medullated  nerve-fibers  are  seen 
most  distinctly  in  transverse  sections.  They  often  hold  in  their 
interstitial  tissue  capillary  vessels  and  arterioles,  which  also 
appear  in  transverse  sections.    In  very  thin  sections  it  often  hap- 


248 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


pens  that  the  nerve-fibers  fall  out,  and  then  we  see  a  roundish 
empty  space  bounded  by  the  sharply-defined  external  perineu- 
rium. The  absence  of  an  endothelial  coat  renders  such  spaces 
easily  recognizable  in  distinction  from  blood-vessels.  (See  Fig. 
148.) 

The  main  mass  of  the  pulp,  as  seen  with  low  powers,  is  com- 
posed of  a  delicate  fibrous  reticulum,  containing  a  large  number 

Fig.  149. 


Segment  of  the  Pulp  of  a  First  Molar  Tooth.    Longitudinal  Section. 

M,  myxomatous  connective  tissue ;  V,  vein ;  C,  capillary  blood-vessel ;  N,  bundle  of  medul- 
lated  nerve -fibers  ;  i^,  terminal  non-meduUated  nerve- fibers;  5,  protoplasmic  layer,  contain- 
ing the  terminations  of  the  nerves ;  0,  layer  of  medullary  corpuscles  in  rovys,  termed  odonto- 
blasts.   Magnified  200  diameters. 


of  bright  corpuscles.  Longitudinal  sections  in  many  instances 
exhibit  delicate  fibrous  bundles  scattered  throughout  the  reticu- 
lar structure  of  the  pulp,  mostly  in  the  neighborhood  of  large 
blood-vessels  and  nerve-bundles.  The  fibrous  reticulum,  in  the 
crown  portion,  is  evenly  distributed ;  in  the  root-portions,  on 
the  contrary,  it  is  much  elongated.  Pulps  composed  of  a  fibrous 
connective  tissue  only,  are  rather  exceptional,  and,  as  it  seems, 


THE  DEXTAL  PULP. 


249 


their  occurrence  is  without  any  relation  to  the  age  of  the  per- 
son. They  are  always  the  result  of  morbid  processes.  Toward 
the  outer  surface  of  the  pulp  the  reticular  structure  is,  as  a  rule, 
denser  than  in  the  middle  portions.     This  peripheral  part  is 


Fig.  150. 


Normal  Pulp  ix  Traxsverse  Szctiox,  Staixed  with  Chloride  of  Gold.    Eeom  a 
Molar  of  a  Youth  Sixteex  Years  Old. 

0,  layer  of  odontoblasts,  arranged  in  rows  of  medullary  corpuscles ;  B,  granular  layer ;  well- 
developed  myxomatous  lymph-tissue  ;  M,  myxomatous  lymph-tissue,  basis-substance  still  pro- 
toplasmic ;  CL,  capillary  blood-vessel  in  longitudinal  section;  CT,  capillary  blood-vessel  in 
transverse  section;  iV'i,  bundle  of  medullated  nerves  in  longitudinal  section;  iV'T,  bundle  of 
medullated  nerves  in  transverse  section.    Magnified  500  diameters. 

surrounded  by  a  wreath  of  elongated  formations  arranged  in  a 
radiating  manner  all  around  the  pulp, — the  so-called  "  odonto- 
blast layer."     (See  Fig.  149.) 


f250      THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH, 

Higher  powers  of  the  microscope  (500  to  600  diameters)  re- 
veal a  minute  reticular  structure,  consisting  of  delicate  fibers  or 
anastomosing  protoplasmic  cords,  Avith  verj^  small  oblong  nuclei 
at  their  points  of  intersection.  The  mesh-spaces  inclosed  by 
this  reticulum  either  look  pale  and  finely  granular  throughout, 
or  there  is,  besides  the  pale  granular  substance,  a  bright  yellow- 
ish body,  either  homogeneous  or  granular,  of  the  size  and  as- 
pect of  a  nucleus.  The  number  of  the  latter  formations  varies 
greatly  in  diflerent  pulps.  "Where  bundles  of  a  fibrous  tissue 
traverse  the  reticulum,  there  the  latter  blend  with  the  former. 
In  the  fibrous  bundles,  besides  the  delicate  fibrillee,  we  see  scanty 
and  small  oblong  nuclei.     (See  Fig.  150.) 

As  mentioned  before,  the  fibrous  connective  tissue  prevails  at 
the  periphery  of  the  larger  blood-vessels  and  nerve-bundles.  In 
transverse  sections  the  latter  invariably  exhibit  a  distinct  fibrous 
sheath  containing  oblong  nuclei, — the  so-called  external  perineu- 
rium. The  nuclei  imbedded  in  the  sheath  do  not  project  above 
the  level  of  the  sheath,  as  is  plainly  observable  on  empty  ones 
where  the  fibers  have  fallen  out,  while  the  endothelia  of  blood- 
vessels of  any  description  invariably  protrude  toward  the  in- 
closed space,  thus  affording  an  excellent  means  of  distinction 
between  blood-vessels  and  empty  nerve-sheaths. 

The  arteries  are  characterized  by  the  presence  of  a  layer  of 
smooth  muscles,  outside  of  which  is  seen  a  slight  fibrous  coat. 
The  layer  of  smooth  muscles  necessarily  thickens  the  walls  of 
the  blood-vessels,  thus  rendering  them  easily  recognizable  in 
transverse  sections.  The  veins,  marked  by  their  large  caliber, 
their  scanty  muscle-fibers,  and  a  fibrous  coat,  are  usually  filled 
with  blood-corpuscles.  The  capillaries  are  composed  of  a  single 
endothelial  layer,  which  is  separated  from  the  adjacent  reticu- 
lum by  an  extremely  delicate  light  rim.  They  are  found  either 
empty  or  containing  a  few  blood-corpuscles. 

In  longitudinal  sections  the  medullated  nerve-fibers  show  the 
well-known  fluted  double  contour  of  considerable  refraction  (the 
sheath  of  Schwann).  Inside  of  this  is  the  myelin  (nerve-fat) 
concealing  the  central  axis-cylinder.  Schwann's  sheath  exhibits 
delicate  oblong  or  spindle-shaped  nuclei,  and  external  to  this  we 
observe  a  very  delicate  layer  of  fibrous  connective  tissue, — "  the 
internal  perineurium."  In  cross-sections  of  the  nerve-bundles 
a  more  or  less  circular  group  of  medullated  nerve-fibers  is  seen, 
each  of  which  in  its  center  exhibits  the  axis-cylinder  in  the  shape 


THE    DENTAL    PULP.  251 

of  a  roundish,  glistening  dot,  the  single  nerve-fibers  being  sepa- 
rated from  one  another  by  the  delicate  internal  perineurium. 
Not  infrequently  capillary  and  arterial  blood-vessels  are  met 
with  between  the  nerve-fibers  which,  at  the  periphery  of  the 
bundles,  blend  with  the  nucleated  sheath  of  the  external  peri- 
neurinra. 

As  to  lymphatics  of  the  pulp,  I  can  say  that  in  some  speci- 
mens I  have  seen  branches  of  vessels  of  the  size  of  veins  with- 
out an  adventitial  coat,^  and  composed  of  large,  flat,  slightly- 
protruding  endothelia.  These  vessels  I  believe  to  be  lymphatics, 
as  they  contained  a  finely-granular  coagulated  albumen,  scanty 
granular  corpuscles,  and  a  very  limited  number  of  blood-cor- 
puscles. As  to  the  distribution  of  lymphatics,  I  must  abstain 
from  positive  statements. 

It  seems  that  pulps  containing  calcareous  globules  afford  the 
best  opportunity  for  the  study  of  the  lymph-vessels,  owing  to 
their  dilated  condition.  Fig.  151  is  taken  from  the  coronal  por- 
tion of  such  a  pulp,  and  beautifully  shows  the  relation  of  the 
lymph-  and  blood-vessels  to  the  bundles  of  medullated  nerves. 

At  the  periphery  of  the  pulp  the  delicate  reticulum  consti- 
tuting the  pulp-tissue  is  very  dense,  and  its  small  meshes  are 
supplied  with  numerous  corpuscles  looking  like  nuclei.  In  this 
layer  we  meet  with  only  narrow  capillary  blood-vessels.  The 
outer  surface  of  this  layer  is  bounded  by  radiating  rows  of  shining 
-corpuscles  of  the  size  and  appearance  of  nuclei.  These  rows  are 
separated  from  one  another  in  a  longitudinal  direction  by  light 
rims,  in  which,  frequently,  delicate  fibrillse  may  be  observed.     • 

In  chromic-acid  specimens  stained  with  carmin,  or,  still 
better,  in  those  treated  with  chloride  of  gold,  high  powers  (1000 
to  1200  diameters)  reveal  an  extremely  minute  reticular  structure 
pervading  all  formations  of  the  pulp-tissue. 

The  formations  at  the  periphery  of  the  dental  pulp,  which 
Avere  termed  "  odontoblasts"  by  J.  Tomes,  and  which  by  some 
observers  have  been  considered  as  epithelium-like  formations, 
under  high  amplifications  exhibit  the  following: 

Longitudinal  bodies,  somewhat  resembling  epithelia,  border 
the  pulp  in  a  radiatory  direction.  Such  a  field  may  appear  in 
the  shape  of  a  finely-granular  protoplasm  or  basis-substance,  in 
which  there  are  imbedded  oblong  nuclei  in  varying  numbers. 
The  nuclei  exhibit  coarse  granules  and  a  dense  reticulum  of  living 
matter,  while  the  elongated  fields  inclosing  the  nuclei  exhibit 


252 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


pale  granules  and  a  delicate  reticulum.  Between  these  latter 
formations  a  narrow  light  rim  is  seen,  wherein  we  observe  some- 
times broad,  sometimes  delicate,  fibrillse  in  connection  with  the 
reticulum  of  neighboring  formations,  accompanied  by  delicate 
conical  offshoots,  which  penetrate  the  surrounding  rims  at  right 


Fig    151 


Vessels  and  Nerm.s  of  the  CRO'\^^  of  a  Pulp  contaimng  Calcareous  Globules. 
N,  N,  large  and  small  bundles  of  medullated  nerves  ;  A.  arteriole  ;   F,  V,  veins ;  C.  eapillarj- 
blood-vessel;  i,  Z,  lymph-vessels ;  J/,  3f,  myxomatous  lymph-tissue.    Magnified  200  diameters. 

angles.  In  many  instances  these  formations  between  the  odonto- 
blasts may  be  traced  into  the  dentinal  fibers,  lodging  in  the 
middle  of  the  dentinal  canaliculi. 

It  is  evident,  from  what  I  have  seen,  that  the  odontoblasts 


THE    DEXTAL    PULP.  253 

furnisli  the  matrix  for  the  basis-substance  of  the  dentine,  whereas 
the  dentinal  fibers,  being  formations  of  living  matter,  originate 
between  the  odontoblasts.     (See  Fig.  152.) 

In  specimens  of  a  nine-months'  foetal  pulp,  sufficiently  stained 
with  chloride  of  gold,  I  have  observed  that  the  medullated  nerve- 
fibers  upon  approaching  the  peripherv  of  the  pulp  are  destitute 
of  their  myelin  sheath,  and  now,  being  bare  axis-cylinders,  split 
into  numerous  extremely  delicate  beaded  fibrillte, — the  '•  axis- 

FiG.  152. 


■<^f 


Skgiiest  of  the  Pclp  of  a  Tempoeaet  To:r>:.  .^liiyEo  with  Chlobidb  of  Gold. 

M,  myxomatous  conneetiTe  tissue :  X.  terminal  non -medullated  nerve-fibers,  in  a  uniformly 
granular  protoplasmic  layer :  0,  rows  of  medullary  corpuscles,  termed  odontoblasts :  F,  dentinal 
fibers  between  the  odontoblasts ;  I),  dentine.    Magnified  12C0  diameters. 

fibrillje.'"  They  are  marked  by  a  dark-violet  color,  and  run  in 
the  light  rims  between  the  rows  of  the  odontoblasts  near  the 
pulp-tissue  proper,  and  are  connected  with  the  odontoblasts  by 
means  of  delicate  conical  ofishoots.  In  some  instances  I  have 
observed  that  these  axis-fib rilliEe  terminated  in  knob-like  extremi- 
ties. But  whether  the  nerve-fibers  directly  anastomose  with  the 
dentinal  fibers  I  am  unable  to  say.  That  an  indirect  connection 
of  the  two  is  established  by  the  intervening  reticulum  of  living 
matter.  I  positively  assert. 


264  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

The  results  of  mv  researches  of  the  normal  pulp  are  as  fol- 
lows: 

I.  The  dental  pulp  is  a  variety  of  connective  tissue  termed 
myxomatous,  representing  an  embryonal  form  of  it.  Some 
authors  have  called  this  form  of  tissue  "  adenoid,"  but  this  term 
is  admitted  to  be  erroneous. 

II.  The  myxomatous  tissue  of  the  pulp  is  intermixed  with  a 
delicate  fibrous  connective  tissue  in  varying  amounts. 

III.  The  pulp-tissue  is  traversed  b}^  a  closed  system  of  blood- 
vessels,— viz,  arteries,  veins,  and  capillaries.  At  least  one  artery 
is  invariably  found  in  the  pulp,  and  it  is  by  no  means  of  excep- 
tional occurrence  that  the  pulp  contains  several  arteries.  Lym- 
phatics in  srnall  numbers  are  also  present. 

IV.  The  pulp-tissue  is  richly  supplied  with  nerves,  which,  in 
the  shape  of  bundles  of  medullated  nerve-fibers,  traverse  the 
myxomatous  tissue.  Toward  the  periphery  of  the  pulp  they 
lose  their  m3^elin  sheaths,  become  non-medullated,  and,  in  the 
shape  of  minute  beaded  fibrillse,  branch  between  the  odonto- 
blasts. 

V.  The  odontoblasts  at  the  periphery  of  the  pulp  are  elon- 
gated protoplasmic  formations  with  rows  of  nuclei.  They  are 
medullary  corpuscles  such  as  we  see  wherever  a  new  tissue  arises 
from  a  former  one.  They  build  up  the  basis-substance  of  the 
dentine  by  solidification  (transformation  into  glue,  and  infiltra- 
tion with  lime-salts).  The  reticulum  of  living  matter  traversing 
the  odontoblasts  remains  unchanged  in  the  basis-substance  of  the 
dentine. 

VI.  The  dentinal  fibers  originate  between  the  odontoblasts. 
Being  formations  of  living  matter,  they  are  in  direct  connection 
with  the  reticulum  of  living  matter, — first  of  the  odontoblasts 
and  afterward  of  the  basis-substance  of  the  dentine.  The  con- 
nection between  the  ultimate  nerve-fibrillse  and  dentinal  fibers 
is  very  probably  an  indirect  one  by  means  of  the  intervening 
reticulum  of  livino;  matter. 


THE    PERICEMENTUM.  2od 

CHAPTER    XX. 

THE   PERICEMENTUM.* 

The  pericementum  (root-membrane,  or  alveolo-dental  peri- 
osteum, or  periodontium,  etc.,  as  it  has  been  termed  by  former 
writers)  is  a  formation  of  fibrous  connective  tissue,  identical 
with  the  periosteum  which  covers  all  bones.  It  consists  of  a 
layer  interposed  between  the  roots  of  the  teeth  and  their  corre- 
sponding bony  alveoli,  and  is  common  to  both.  It  is  continu- 
ous with  the  connective  tissue — the  so-called  sub-mucous  layer 
of  the  guni — and  with  the  periosteum  of  the  maxillse.  Its  fibers 
are  connected  with  the  cementum  of  the  root  as  well  as  with 
the  wall  of  the  alveolus.  A  few  writers  have  described  the 
pericementum  as  a  double  membrane,  one  portion  of  which 
belongs  to  the  root,  the  other  to  the  alveolus:  we  ourselves  have 
not  been  able  to  see  anything  that  justifies  such  a  discrimination. 
In  many  of  the  specimens  examined,  the  connective-tissue  bun- 
dles of  the  pericementum  may  be  traced  from  the  socket  to  the 
cementum  of  the  root  of  the  tooth,  or  in  connection  with  the 
reticular  structure  in  the  vicinity  of  the  root.  Exceptionally 
we  see,  close  around  the  root,  a  thin  layer  of  very  dense  and  fine 
fibers,  the  general  direction  of  which  is  not  quite  identical  with 
that  of  the  connective  tissue  which  produces  the  main  mass  of 
the  pericementum.  The  relations  between  the  soft  and  the 
hard  formations  of  the  jaws  are  very  plain  in  specimens  obtained 
from  grown  cats,  and  in  all  essential  points  are  in  accordance 
with  those  perceived  in  specimens  taken  from  the  liuniau  jaw. 

The  course  pursued  by  the  connective-tissue  bundles  is  slightly 
wavy  and  oblique,  starting  from  the  cementum  and  running  up- 
ward toward  the  alveolus.  The  bundles  of  this  tissue  are  dense, 
without  many  decussations.  The  parallel  direction  of  the  bun- 
dles begins  to  change  into  a  diverging  one  at  about  the  height 
of  the  border  of  the  socket,  where  the  bundles  become  coarser, 
decussate,  and  thus  produce  the  elastic  connective-tissue  cushion, 
termed  the  gum. 

From  the  anatomical  disposition  of  the  pericementum,  con- 
clusions may  be  drawn  as  to  its  physiological  action.  It  is  evident 
that  the  relatively  soft  and  elastic  layer  between  the  two  bony 

*  "  Pericementum  and  Pericementitis.'     Dental  Cosmos.  1879-1880. 


256  THE    ANATOMY    AND    PATHOLOaY    OF    THE    TEETH. 

formations — the  cementum  and  tlie  alveolus — is  designed  to 
lessen  the  concussion  upon  the  jaw-bones  during  mastication. 
The  oblique  direction  of  the  connective-tissue  bundles  is  the 
most  favorable  for  the  suspension  of  the  tooth  within  its  socket, 
as  the  bundles  correspond  to  the  funnel  shape  of  the  socket,  in 
the  center  of  which  is  situated  the  conical  root  of  the  tooth. 
The  elasticity  of  the  layer  of  pericementum  admits  of  a  slight 
degree  of  motion  of  the  roots;  hence  we  understand  the  forma- 
tion of  facets  on  the  approxiraal  surfaces  of  the  crowns  of  the 
teeth  in  crowded  maxillary  arches. 

Fig.  153. 


Pekicemextum  of  Myxomatous  Structure. 

D,  dentine ;  C,  cementum  of  neck ;  P,  pericementum  ;  M,  multinuclear  body ;    V,  capillary 
blood-vessel ;  F,  fat-globule  ■uith  a  vacuole.    Magnified  500  diameters. 

We  observe  two  varieties  of  pericementum, — one  of  a  reticu- 
lar structure,  termed  myxomatous;  the  other  altogether  fibrous. 
The  myxomatous  variety  I  have  met  with,  as  a  rule,  in  young 
individuals.  It  consists  of  delicate  fibers,  or  bundles  of  fibers, 
in  a  net-like  arrangement,  and  having,  in  many  instances,  round 
or  oblong  nuclei  at  the  points  of  intersection.  The  meshes  con- 
tain either  a  hyaline,  apparently  structureless,  sometimes  finely- 
granular  basis-substance,  or  they  hold  protoplasmic  bodies,  pro- 
vided with  a  varying  number   of  nuclei.     The  nearer  to  the 


THE    PERICEMENTUM.  25/ 

cementum,  the  narrower  is  the  myxomatous  reticulum,  and  the 
smaller,  therefore,  are  the  inclosed  protoplasmic  bodies.  The 
latter,  in  the  immediate  vicinity  of  the  cementum,  stand  in  more 
or  less  regular  rows,  entirely  analogous  to  the  protoplasmic 
bodies  around  the  developing  bone-tissue,  known,  since  Gegen- 
baur,  as  "osteoblasts."  Some  of  the  meshes  of  the  myxomatous 
tissue  are  considerably  larger  and  contain  multinuclear  proto- 
plasmic bodies,  termed  "  myeloplaxes"  by  Robin,  of  Paris ; 
"  giant-cells"  by  R.  Virchow,  of  Berlin,  and  "  myeloid  cells"  by 
English  authors.  Other  meshes  hold  fat-globules,  which,  in 
specimens  preserved  and  hardened  in  a  solution  of  chromic  acid, 
very  often  contain  closed  spaces, — so-called  vacuoles.  The 
myxomatous  reticulum  is  traversed  by  numerous  blood-vessels, 
mainly  capillaries  and  veins,  some  of  which  may  be  seen  enter- 
ing the  medullary  spaces  of  the  compact  bone  of  the  wall  of  the 
alveolus,  and  in  connection  with  the  capillary  system  of  the  can- 
cellous portion  of  the  alveolus.  I  have  met  with  but  few  nerve- 
fibers  in  my  specimens. 

Fig.  153  illustrates  a  portion  of  the  myxomatous  variety  of 
pericementum  as  shown  with  a  relatively  low  power.  High 
amplification  of  the  microscope  plainly  demonstrates  the  delicate 
reticular  structure  of  all  protoplasmic  bodies;  the  reticulum 
being  visible  not  only  in  the  contents  of  the  meshes,  but  also 
within  the  fibers  of  the  myxomatous  reticulum.  The  latter 
feature  is  best  recognizable  on  specimens  deeply  stained  with 
chloride  of  gold.  The  apparently  structureless  or  indistinctly 
granular  myxomatous  basis-substance,  held  in  the  meshes  of  the 
myxomatous  reticulum,  proves  to  be  of  a  reticular  structure  just 
as  well  as  the  protoplasm  itself. 

The  second  variety  of  pericementum  is  built  up  of  fibrous 
connective  tissue,  which  prevails  in  adults  and  persons  of  ad- 
vanced age.  The  bundles  of  the  fibrous  connective  tissue  may 
be  uniform  in  width  throughout  the  whole  pericementum ;  or 
there  exists  a  zone  of  tissue  of  myxomatous  or  indistinctly 
fibrous  character  close  around  the  cementum.  The  bundles  are 
built  up  of  a  number  of  fibers  which  hold  a  varying  amount  of 
protoplasmic  bodies ;  as  a  rule,  more  numerous  the  nearer  to 
the  cementum.  On  the  latter  there  maybe  found  rows  of  osteo- 
blasts or  scattered  protoplasmic  bodies  alternating  with  bundles 
of  a  delicate  connective  tissue,  which  are  directly  attached  to 
the  cementum.     In  a  few  instances  we  see  rows  of  osteoblasts, 

18 


'lol 


THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH. 


the  refracting  power  of  which  has  been  considerably  augmented. 
Such  corpuscles  look  shining  and  structureless,  evidently  because 
of  a  deposition  of  lime-salts.  The  fibrous  variety  of  the  perice- 
mentum also  contains  fat-globules,  sometimes  in  a  surprisingly 
large  quantity. 

High  magnifying  powers  of  the  microscope  reveal  a  struc- 
ture of  the  fibrous  connective  tissue,  as  follows  :    The  fibers,  a 
certain  number  of  which  combine  in  the  formation  of  a  bundle, 
are  delicate  spindles,  directly  connected  wdth  one  another  at  their 
pointed  ends.     These  spindles  are  separated  from  each  other  by 
narrow  layers  of  a  light  substance,  to  the  presence  of  which 
Tomsa  first  drew  attention,  and  for  which  he  proposed  the  term 
"  cement-substance."     This  substance  is  doubtless  kindred  to 
the  gluey  basis-substance  which  mainly  builds  up  the  spindles  of 
the  connective  tissue.      The  interstices  between  the  spindles  are 
traversed  in  a  vertical  direction  by  extremely  minute  threads 
every  way  analogous  to  the  thorns  in  the  cement-substance  sur- 
rounding epithelial  elements.     These  threads  in  many  instances 
are  visilolc  in  specimens  hardened  by  the  chromic-acid   solu- 
tion ;  they  become  very  plain  when  thin  sections  have  been  im- 
mersed in  a  half  per  cent,  solution  of  chloride  of  gold  for  one 
or  two  hours,  or  until  the  specimen  has  assumed  a  dark-violet 
color.     If  the  stain  be  complete,  we  also  recognize  that  the 
spindles  are  not  homogeneous,  as  they  look  in  fresh,  unstained 
specimens,  but  are  rather  traversed  by  a  delicate,  dark-violet 
reticulum,  the  points  of  intersection  of  which  are  slightly  thick- 
ened, and  thus  represent  granules.     (See  Fig.  154.) 

Between  the  spindles  of  the  basis-substance  protoplasmic 
bodies  are  seen  the  formerly  so-called  connective-tissue  cells. 
Some  of  these  bodies  exhibit  shining,  compact,  oblong  nuclei, 
with  a  certain  amount  of  surrounding  protoplasm,  while  others 
are  devoid  of  nuclei,  and  split  into  spindle-shaped  or  polygonal 
lumps,  which  in  size  and  shape  fully  correspond  to  the  element- 
ary formations  of  the  fibrous  basis-substance.  Where  there  is 
a  central  nucleus,  it  is  invariably  bounded  by  a  light  rim,  which 
is  pierced  by  radiating  thorns.  The  latter  connect  the  circum- 
ference of  the  nucleus  with  the  granules  of  the  protoplasm  next 
to  the  nucleus.  The  protoplasm  under  all  circumstances  exhib- 
its the  well-known  reticular  structure.  From  the  periphery  of 
a  protoplasmic  body,  each  being  surrounded  by  a  light  rim, 
minute  threads  spring  forth,  and  run  into  the  reticulum  within 


THE    PERICEMENTUM.  259 

the  spindles  of  the  basis-substance.  The  same  relations  are  seen 
in  protoplasmic  bodies  next  to  the  cementum, — the  so-called 
osteoblasts.  The  offshoots  of  these  formations  run  partly  to  the 
spindles  of  the  basis-substance  and  partly  into  the  light  reticu- 
lum within  the  cementum.  In  some  instances,  between  the 
cementum  and  the  osteoblasts  there  is  interposed  a  small  layer 
of  fibrous  basis-substance  in  the  shape  of  delicate  slender  spin- 
dles. The  walls  also  of  the  capillaries,  consisting  of  a  single 
layer  of  endothelia,  are  connected  wdth  the  neighboring  spindles 
of  the  basis-substance  by  means  of  delicate  threads,  which  tra- 
verse the  light  rim  around  the  blood-vessels, — the  so-called  peri- 

EiG.   154. 


Pericementum  of  Fibrous  Structure. 


f 


C,  cementum  of  root;  PX, pericementum,  the  fibers  of  which  are  built  up  of  spindles,  in 
longitudinal  sertion ;  PF,  pericementum,  the  elementary  spindles  of  which  are  finer,  and  cut 
obliquely  ;  P\  P-,  protoplasmic  bodies,  either  so-called  connective-tissue  corpuscles  or  so-called 
osteoblasts.    Magnified  1200  diameters. 

vascular  space.  Last!}',  such  offshoots  run  also  into  the  light 
reticulum  of  the  bone-tissue,  where  the  pericementum  is  attached 
to  the  wall  of  the  alveolus. 

In  its  juvenile  condition  the  pericementum  represents  a  myxo- 
matous connective  tissue,  the  fibrous  portion  of  which  is  rela- 
tively scanty,  while  the  protoplasmic  portion  prevails.  In  this 
instance  two  varieties  of  basis-substance  occur, — viz,  the  fibrous, 
building  up  the  reticulum,  and  the  myxomatous,  filling  a  cer- 
tain portion  of  the  meshes.  This  condition  arises,  first,  from  the 
indifierent  or  embryonal  tissue,  not  only  in  the  pericementum, 
but  in  all  formations  of  connective  tissue  which,  when  fully  de- 


260 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


veloped,  exhibit  a  fibrous  structure.  The  only  way  to  explain  the 
formation  of  the  myxomatous  tissue  is  that  a  part  of  the  proto- 
plasm constituting  the  embryonal  elements  remains  unchanged, 
a  part  is  transformed  into  spindles  of  myxomatous  reticulum, 
and  a  part  into  myxomatous  basis-substance. 

"Whereas  the  myxomatous  variety  of  pericementum  is  rich  in 
blood-vessels,  the  fibrous  variety  is  bat  scantily  provided  with 
them.     The  broadest  portion  of  the  pericementum,  that  around 


Fig.  155. 


Coils  op  Arterioles  ix  the  Pericementum.    Horizontal  Section. 

C,  eementum  at  the  apex ;  L,  longitudinal  fibers  of  pericementum  ;  T,  transverse  fibers  of 
pericementum ;  <7,  C,  coils  of  arterioles ;  N,  N,  bundles  of  meduUated  nerves  in  transverse  sec- 
tion.   Magnified  100  diameters. 

the  apex  of  the  root,  shows  peculiarly  tortuous  arteries  and 
arterioles,  in  some  places  coiled  into  tuft-like  formations.  C. 
Wedl  was  the  first  to  describe  such  arterial  tufts  in  the  perice- 
mentum. Fig.  155  is  an  illustration  of  two  arterial  coils.  Tor- 
tuous arteries  we  invariably  find  in  tissues  and  organs  exposed 
to  frequent  changes  in  their  bulk,  and  it  seems  that  the  slight 
mobility  of  the  tooth,  owing  to  the  varying  amount  of  perice- 
mentum, accounts  for  the  presence  of  arterial  coils. 


ERUPTION    OF    THE    TEETH. 


261 


CHAPTER  XXL 


ERUPTION  OF  THE  TEETH. 


For  the  first  eight  or  ten  mouths  after  birth,  infants  require 
only  liquid  food,  and  in  a  normal  condition  they  have  during 
that  period  no  teeth  above  the  gums.  Instead  of  teeth,  upon 
the  anterior  portion  of  the  jaws  we  observe  comparatively  hard 
and  rough  eminences  of  the  mucous  membrane,  designed  to 
hold  the  nipple  of  the  mother's  breast  in  the  process  of  sucking. 
At  the  time  of  birth  the  cusps — cutting-edges — of  the  crowns 
of  most  of  the  temporary  teeth  are  situated  on  a  level  with  the 
alveolar  process,  covered  only  by  the  mucous  membrane.  The 
calcification  of  the  teeth  commences  at  their  cusps  or  cutting- 


,30ms 


Diagram  of  Eruption  of  the  Temporary  Teeth. 

edge,  and  gradually  extends  to  the  root.  The  first  teeth  usually 
make  their  appearance  about  the  sixth  or  seventh  month  after 
birth,  although  no  definite  time  can  be  predicated.  There  are 
several  cases  on  record  of  children  born  with  teeth;  while  on  the 
other  hand,  the  author  has  seen  children  who  began  to  cut  their 
teeth  no  earlier  than  at  the  age  of  twelve  or  sixteen  months. 
When  the  crowns  of  the  temporary  teeth  make  their  appearance 
through  the  gum,  the  roots  are  but  partially  formed,  as  is  illus- 
trated in  Fig.  120,  taken  from  an  article  by  C.  X.  Peirce.* 

The  time  considered  normal  for  the  eruption  of  the  tempo- 
rary teeth  is  as  follows.     (See  Fig.  156.) 

"^Dental  Cosmos,  Auo-ust,  1884. 


262 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


-4-5  y 


LiAGRAM  OF  Eruption  of  Permanent  Teeth  of  the  Upper  Jaw. 


Fig.  158 


Diagram  of  Eruption  of  Permanent  Teeth  of  the  Lower  Jaw. 


ERUPTIOX    OF    THE    TEETD. 


263 


The  central  incisors  from  the  fifth  to  the  seventh  month. 

The  lateral  incisors  from  the  seventh  to  the  ninth  month. 

The  first  molars  from  the  twelfth  to  the  fourteenth  month. 

The  cuspids  from  the  fourteenth  to  the  eighteenth  month. 

The  second  molars  from  the  twentieth  to  the  thirtieth  month. 

The  temporary  teeth,  under  normal  conditions,  remain  in  their 
respective  places  in  the  mouth  until  they  are  replaced  by  the 
permanent  teeth,  the  first  of  which  are  usually  erupted  at  about 
the  sixth  year.  Occasionally  we  meet  with  children  who  shed 
their  teeth  earlier, — at  the  fifth  year  or  even  before ;  while  in 
other  instances  the  permanent  teeth  do  not  appear  before  the 


Fig.  159. 


Sheddixg  of  the  Temporary  and  Appearaxce  of  the  Permanent  Teeth,  between 
THE  Fifth  and  Sixth  Years. 

eighth  or  ninth  year.  We  frequently  find  that  a  patient  has  re- 
tained one  or  two  temporary  teeth  up  to  the  thirtieth  or  fortieth 
year  of  his  age,  these  being  sometimes  quite  firm  in  their 
sockets. 

The  time  considered  normal  for  the  tem.porary  teeth  to  fall 
out  and  to  be  replaced  by  their  successors  is  as  follows.  (See 
Figs.  157  and  158.) 

The  central  incisors  from  the  sixth  to  the  seventh  year. 

The  first  molars  from  the  sixth  to  the  seventh  year. 

The  lateral  incisors  from  the  seventh  to  the  ninth  year. 

The  upper  first  bicuspids  from  the  eighth  to  the  tenth  year. 


264  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH, 

The  lower  cuspids  from  the  eighth  to  the  eleventh  year. 

The  lower  lirst  bicuspids  from  the  ninth  to  the  eleventh 
year. 

The  upper  cuspids  from  the  tenth  to  the  twelfth  year. 

The  second  upper  and  lower  bicuspids  from  the  tenth  to  the 
twelfth  year. 

The  second  molars  from  the  twelfth  to  the  thirteenth  year. 

The  third  molars  from  the  fifteenth  to  the  forty-fifth  year. 

On  the  first  appearance  of  the  permanent  teeth,  their  roots, 
like  those  of  the  temporary  teeth  at  that  period,  are  not  com- 
pleted. A  consideration  of  the  time  of  calcification  of  the  roots 
of  the  teeth  is  therefore  important,  especially  as  the  teeth  of 
young  patients  often  are  attacked  by  caries,  and  sometimes  by 
pulpitis.  (See  Fig.  159.)  It  is  evident  that  when  the  pulp  of  a 
tooth  with  an  incomplete  root  dies,  the  saving  of  that  tooth 
becomes  very  problematical. 


CHAPTER    XXII. 

ABSORPTION   OF  TEMPORARY  TEETH. 

At  a  certain  age  the  temporary  teeth  become  loose,  and  some- 
times fall  out  without  causing  pain  or  loss  of  blood. 

A  temporary  tooth  shed  in  this  manner  usually  exhibits  only 
a  croAvn  somewhat  hollowed  out  underneath,  in  the  place  whence 
the  former  root  united  with  it,  or  a  small  portion  of  the  root 
may  still  be  present.  Upon  macroscopical  examination  we  find 
the  concave  bottom  of  the  crown  worn  away  into  irregular 
grooves  and  pits.  Some  of  these  bays  may  contain  small 
pieces  of  vascularized  soft  tissue,  the  "  carneous  hody^'  of  older 
writers.  Originally,  the  temporary  teeth,  like  those  of  the  per- 
manent set,  are  possessed  ■  of  roots  which  gradually  become 
shortened  by  absorption,  as  the  growth  of  the  permanent  teeth 
proceeds. 

Frank  Abbott  has  thoroughly  studied  the  appearances  of  the 
absorption  of  the  deciduous  teeth,  and  has  published  his  results 


ABSORPTION    OF    TEMPORARY    TEETH.  265 

in  an  essay.*  I  fall}^  concur  with  the  author  in  all  essential  points, 
and  quote  from  him  as  follows : 

"  The  assertion  of  Tomes,  that  absorption  is  due  to  the  pres- 
ence of  a  freely-vascularized  papilla,  does  not  explain  the  decrease 
of  the  dental  tissues,  for  the  papilla  is  nothing  but  medullary 
tissue,  such  as  we  meet  with  in  any  part  of  the  organism,  where 
one  tissue  is  about  to  change  into  another.  Such  a  papilla  may 
be  the  cause  of  the  absorption,  as  well  as  its  result.  Another 
assertion,  that  the  medullary  cells  eat  out  the  dental  tissues  by 
their  active  growth,  or  by  their  amoeboid  motions,  is  insufficient 
to  explain  the  loss  of  the  lime-salts  in  the  dental  tissues,  as  well 
as  to  explain  the  presence  of  circular  or  semi-circular  excava- 
tions and  bays  so  characteristic  of  the  melting  process  of  the 
cementum  and  dentine  of  deciduous  teeth. 

"Since  we  know  that  pieces  of  dead  bone  or  ivory  may 
be  absorbed,  with  figures  similar  to  those  found  on  the  surface 
of  temporary  teeth,  the  idea  possibly  becomes  admissible  that, 
owing  to  the  presence  of  an  acid,  first  the  lime-salts  are  dissolved 
away  within  certain  territories  of  the  dead  bone-tissue,  in  a 
merely  chemical  or  passive  manner,  whereupon  the  soft  medul- 
lary tissue  penetrates  the  spaces  thus  established.  Quite  differ- 
ent, however,  will  be  the  conception  of  this  process,  if  we  bear 
in  mind  that  the  temporary  teeth,  as  well  as  the  permanent  ones, 
are  made  up  of  living  tissues,  and  an  active  participation  of  these 
tissues  must  be  expected  in  the  process  of  transformation  of  the 
dental  into  the  medullary  tissue.  As  the  process  of  absorption 
is  closely  allied  to  the  process  of  inflammation,  and  active 
changes  of  the  dental  tissues  have,  beyond  any  doubt,  been 
proven  to  follow  inflammation,  we  may  a  2)nori  expect  such 
changes  of  the  bone-tissue  of  the  temporary  teeth  in  the  process 
of  absorption  also." 

The  process  of  absorption  of  deciduous  teeth  is,  indeed,  closely 
allied  to  the  inflammatory  process,  and  may  be  considered  as  a 
physiological  type  of  tissue-changes  owing  to  the  presence  of 
some  irritating  agency.  The  dissolution  of  lime-salts  in  bone, 
as  well  as  that  of  the  hard  tissues  of  the  teeth,  probably  is  due 
to  the  presence  of  lactic  acid.  The  dissolution  of  the  lime-salts 
may  invade  dead  bone-tissue,  or  invade  pieces  of  ivory  implanted 

*•' Microscopical   Studies  upon   the  Absorption  of  the   Eoots   of  Temporary 
Teeth." 


266 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH, 


in  a  living  tissue.  In  such  dead  bone  or  ivory  we  likewise^ob- 
serve  the  disappearance  of  the  lime-salts  in  the  bay-like'excava- 
tions,  which  later  are  tilled  with  a  living  tissue  growing  into  the 
excavations  from  without. 

When  a  temporary  tooth  begins  to  be  absorbed,  its  constituent 

Fig.  160. 


Absorption  of  Cementum  of  a  Temporary  Tooth. 
D,  cement-corpuscles  in  division ;  iV,  cement-corpuscles  unchanged ;   B,  basis-substance  of 
cementum  ;  M,  M,  multinuelear  protoplasmic  bodies  ;  F,  fibrous  connective  tissue.    Magnified 
500  diameters. 


tissues  unquestionably  are  alive,  and  consequently  it  is  reason- 
able to  assume  that  the  outermost  layer  of  the  root,  first  ex- 
posed to  the  irritation,  will  react  as  other  living  tissues  do  in  the 
inflammatory  process. 


ABSORPTIOX    OF    TEMPORARY    TEETH.  267 

Whether  or  not  dentine  and  enamel  actively  participate  in  the 
process  of  absorption  is  doubtfnl,  and  np  to  the  present  day 
unproven. 

Absorption  of  Cementum. — The  first  changes  due  to  absorp- 
tion are  semi-circular  excavations  or  bays  on  the  surface  of  the 
root  of  a  temporary  tooth,  filled  with  embryonal  corpuscles  or 
multinuclear  protoplasmic  bodies,  in  connection  with  the  myxo- 
matous or  fibrous  connective  tissue  of  the  pericementum. 
According  to  Abbott,  isolated  excavations  may  be  seen,  the 
connection  of  which  with  the  outer  surface,  though  not  observa- 
ble in  the  specimen,  may  be  present  above  or  below  the  plane 
of  the  section.  He  says,  "  By  closely  watching  excavations  of  a 
more  recent  date,  at  the  periphery  of  earlier  ones  which  are  in 
communication  with  the  pericementum,  we  notice  that  the  lime- 
salts  and  the  basis-substance  proper  are  missing,  and  are  replaced 
by  a  uniformly-granular  protoplasm,  or  a  varying  number  of 
faintly-marked  medullary  elements,  each  of  which  may  contain 
a  central  nucleus." 

Another  proof  that  the  tissue  of  the  cementum  reacts  upon 
the  irritation  is  that  the  cement-corpuscles  nearest  to  the  eroded 
surface  frequently  are  found  enlarged,  glossy,  and  split  up  into 
smaller  pieces.     (See  Fig.  160.) 

The  result  of  such  changes  is  the  appearance  of  embryonal 
or  medullary  corpuscles  at  the  border  of  the  excavation,  or  of 
multinuclear  bodies,  formerly  the  territories  of  the  cementum, 
now  reduced  to  protoplasm.  This  indifferent  tissue  appears 
connected  with  fibrous  tissue,  abundantly  supplied  with  newly- 
formed  blood-vessels.  ]^ot  infrequently  the  latter  tissue  also 
holds  trabeculse  of  newly-formed  bone,  sometimes  to  such  an 
extent  that  the  widened  sockets  of  the  temporary  teeth  are  filled 
with  a  considerable  amount  of  cancellous  bone-tissue. 

Absorption  of  Dentine. — Dentine,  during  the  process  of 
absorption,  if  examined  with  low  powers  of  the  microscope  at 
the  corroded  surface,  exhibits  a  number  of  bay-like  excavations 
similar  to  those  seen  in  bone-tissue  and  the  cementum  in  this 
process.     (See  Fig.  161.) 

Since  we  know  that  dentine,  like  bone,  is  formed  from  medul- 
lary tissue  clustered  together  in  territories,  we  are  not  surprised 
to  find  such  semi-circular  excavations  at  the  exposed  surface  of 
dentine  during  the  process  of  absorption.  The  bays  are  filled 
either  with  clusters  of  embryonal  corpuscles,  or  multinuclear 


268 


THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 


protoplasmic  bodies,  frequently  observed  in  growing  as  well  as 
in  inflamed  bone-tissue.  These  formations  are  continuous  with 
fibrous  connective  tissue  holding  the  shortened  temporary  tooth 
in  position.  An  important  question  is,  whether  or  not  the  den- 
tine of  deciduous  teeth  participates  actively  in  the  production  of 

Fig.  161. 


Absorption  of  Dentine  of  Temporary  Tooth. 
U,  unchanged  dentine  ;  D,  decalcified  dentine  :  B,  zone  of  bay -like  excavations  ;  F,  fibrous 
connective  tissue.    Magnified  100  diameters. 


embryonal  elements,  which  afterward  develop  into  fibrous  con- 
nective tissue.  This  question  is  as  yet  unsettled.  If,  however, 
we  bear  in  mind  that  a  deciduous  tooth  with  a  living  pulp,  as  a 
rule,  remains  sensitive  up  to  the  time  of  detachment  from  the 
pericementum,  the  possibility  of  such  participation  cannot  be 


ABSORPTION    OF    TEMPORARY    TEETH. 


269 


denied.  Abbott  is  iu  favor  of  assuiriing  it,  since  he  observed  a 
widening  of  the  dentinal  canaliculi  at  the  borders  of  the  bays, 
with  an  increase  of  the  living  matter  of  the  dentinal  fibers. 

Fields  of  absorption  are  frequently  met  with  in  the  dentine, 
some  distance  away  from   the  eroded  surface,  and  apparentlv 

Fig.  162. 


Absorption  of  Dentine  of  a  Temporary  Tooth. 

-D,  dentine  without  signs  of  reaction  ;  /,  isolated  medullary  spaces;  .S",  medullary  space  filled 
with  indifferent  corpuscles  and  fibrous  connective  tissue  :  M,  multinuclear  body  filling  a  bay  ; 
T,  newly-formed  territories  of  bone-tissue;  X,  lamellated  bone-tissue:  F,  fibrous  connective 
tissue.    Magnified  500  diameters. 

isolated.  Again,  we  cannot  deny  the  possibility  that  such  ex- 
cavations may  have  been  in  connection  with  the  surface,  and^are 
filled  with  ingrowing  embryonal  or  myxomatous  tissue.  (See 
Fig.  162.) 


"270  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

It  is  known  since  J.  Tomes,  that  the  bays  of  the  eroded  den- 
tine are  often  found  filled  with  bone-tissue,  either  in  the  shape 
of  territories  or  of  laraellated  bone.  The  latter  may  reach  such 
a  degree  of  development  that  it  produces  an  almost  continuous 
layer  all  around  the  absorbed  tooth. 

Absorption  of  Enamel. — This  process  is  but  little  studied,  on 
account  of  its  exceptional  occurrence,  which  has  been  mostly 
observed  in  the  temporary  molars. 

Bay-like  excavations,  similar  to  those  observed  in  the  dentine 
and  cementum,  occur  in  absorbed  enamel.  Chas.  Tomes  has 
noticed  such  bays  of  the  enamel  filled  with  newly-formed  bone- 
tissue,  the  same  as  we  observe  in  absorption  of  dentine.  He 
attributes  this  rare  occurrence  to  the  overlapping  of  the  cement 
on  the  edffe  of  the  enamel. 


CHAPTER   XXIII. 

PHYSIOLOaY   OF  THE  HARD   DENTAL  TLSSUES. 

The  latest  researches  into  the  minute  anatomy  of  the  dental 
tissues — researches  described  in  previous  chapters — necessarily 
alter  the  views  hitherto  held  concerning  the  nutrition  of  those 
tissues.  Enamel  has  been  considered  to  be  a  mere  deposit, 
as  it  were,  of  purified  lime-salts ;  a  coat  of  mail  destitute  of  life. 
The  authors  in  the, foregoing  chapters  have  demonstrated  the 
presence  of  living  matter  between  and  within  the  enamel- 
prisms,  and  consequently  affirm  that  enamel  is  a  tissue  with 
properties  of  life,  although  in  minimum  degree.  Dentine  has 
long  been  known  to  be  a  tissue  extremely  sensitive  throughout, 
especially  at  the  interzonal  layer  bordering  the  enamel. 

Xothing,  however,  was  known  as  to  the  seat  of  life  in  dentine, 
until  myself  and  others  endeavored  to  prove  not  only  that  the 
dentinal  fibers  and  their  coarse  ofishoots  are  formations  of  living 
matter,  but  that  the  basis-substance,  so  rich  in  lime-salts,  is 
traversed  by  an  extremely  delicate  filigree  of  living  matter  as 
well. 

With  the  facts  before  us,  we  may  attempt  to  approach  the 
solution  of  a  hitherto  insoluble  riddle, — viz,  the  nutrition  of  the 


PHYSIOLOGY    OF    THE    HARD    DEXTAL    TISSUES.  271 

dentine  and  of  the  enamel.  N"o  close  observer  will  doubt  that 
the  nutrition  of  the  hard  tissues  of  the  teeth  is — and  must  be — 
an  active  one.  This  is  proven  not  only  by  the  growth  of  these 
tissues,  but  also  by  the  same  tissues'  strikingly  rapid  loss  of  lime- 
salts  in  constitutional  diseases,  such  as  neurasthenia,  antemia, 
etc.,  and  even  in  pregnancy.  How  are  the  lime-salts  deposited 
in  the  dentine,  and  how  can  they  be  removed  to  such  a  degree 
that  dentine,  originally  hard,  becomes  in  a  few  months  soft  and 
brittle  ? 

Looking  at  the  dentinal  canaliculi  with .  the  highest  obtain- 
able powers  of  the  microscope,  we  see  between  the  dentinal 
liber  and  the  walls  of  the  canaliculus  a  narrow,  light  space,  evi- 
dently filled  with  liquid,  which  serves  for  the  carrying  of  nour- 
ishing material  to  the  dentine,  and  for  the  carrying  of  effete 
material  away  from  it.  More  than  this,  even  the  ultimate 
fib  rill  as  of  living  matter  within  the  basis-substance  are  sur- 
rounded by  a  delicate  light  space  holding  substances  that  serve 
the  same  purposes. 

If,  besides  these  points,  we  observe  that  the  dentinal  fibrillee 
are  of  a  vacuoled  structure,  and  that  the  ultimate  fibrillse  have 
a  rosary  or  beaded  appearance,  we  are  prepared  to  acknowledge 
the  possibility  that  in  living  dentine  the  living  matter  proper  is 
at  no  time  perfectly  at  rest ;  that,  on  the  contrary,  it  is  contract- 
ing, slowly  but  continuously,  and  that  through  its  contractions 
it  not  only  stirs  the  surrounding  column  of  liquid,  but  pumps, 
as  it  were,  nourishing  material  into  the  minutest  fields  of  the 
dentine,  or  away  from  them.  The  chemical  character  of  the 
liquid  may  explain  the  dissolution  of  a  certain  amount  of  the 
lime-salts  deposited  in  the  blocklets  of  the  basis-substance, 
which  salts,  thus  being  rendered  effete,  may  be  carried  into  the 
lymphatics  of  the  pulp,  and  thence  into  the  ly-mph-system  of  the 
body  for  further  elimination.  Why,  in  one  instance,  nourish- 
ing material  should  be  carried  from  the  blood-vessels  of  the 
pulp  into  the  dentine,  and  in  another  instance  carried  away  from 
the  dentine  into  the  lymphatics,  w^e  are  as  yet  unable  to  under- 
stand. 

What  I  have  stated  concerning  the  tissue  of  dentine  unques- 
tionably holds  good  for  the  tissue  of  the  enamel  also.  The 
latter  being  at  the  periphery  of  the  crown  of  the  tooth,  farthest 
away  from  the  source  of  nutrition,  and  but  scantily  supplied 
with  living  matter,  its  nutrition  must  be  extremely  slow.     Still, 


272  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

every  dentist  must  have  observed  instances  of  softening  of  the 
enamel  as  the  result  of  constitutional  ailments. 

Ee-calcification,  re-hardening  of  the  enamel,  though  denied 
by  E.  Baume,  is  certainly  a  fact.  The  structure  of  the  enamel- 
fibers  between  the  prisms,  as  well  as  of  those  traversing  the 
latter,  points  to  the  identity  of  the  process  of  nutrition  and  de- 
nutrition  with  that  in  the  dentine.  To  preserve  the  life  of  the 
dentine  and  of  the  enamel,  it  is  not  necessary  to  have  the  entire 
pulp  of  a  tooth  intact.  The  experiments  of  W.  Plerbst  jjrove, 
on  the  contrary,  that  only  a  portion  of  the  pulp-tissue  left  alive 
in  the  pulp-canals  is  capable  of  keeping  alive  the  dentine  and 
enamel  of  the  crown  of  a  tooth,  as  I  will  show  in  a  subsequent 
chapter. 

Another  important  point  seems  to  be  explained  satisfactorily 
by  our  researches  into  the  structure  of  the  dentine, — i.e.,  the 
sensitiveness  of  this  tissue.  So  striking  is  this  fact  that  a 
thoughtful  observer  such  as  J.  Tomes  alluded  to  the  possibility  of 
the  dentinal  fibrillse  being  nerves.  Such  a  view  is  not  tenable, 
for  two  reasons : 

First,  it  is,  according  to  our  advanced  conceptions  of  histology, 
impossible  to  admit  of  the  existence  of  a  connective  tissue  hold- 
ing nerves  alone  in  its  constitutent  soft  parts.  Second,  neither 
have  we,  nor  has  G.  Retzius  in  his  recent  investigations  been 
able  to  trace  a  direct  inosculation  of  the  dentinal  fibrillse  with 
the  axis-fibrillse  of  the  nerves,  so  abundantly  distributed  through- 
out the  periphery  of  the  pulp-tissue.  As  soon,  however,  as  we 
admit  that  the  dentinal  fibrillfe  are  formations  of  living  matter, 
the  same  as  are  the  nerves,  all  ditficulties  vanish  in  explaining 
the  transmission  of  sensation  from  the  periphery  of  the  dentine  to 
the  nerves  of  the  pulp-tissue.  Living  matter  is  contractile  matter, 
according  to  Heitzmann.  Nerves  are  made  up  of  living  matter, 
and,  owing  to  their  reticulated  or  beaded  structure,  are  fittest 
for  that  transmission  of  contractions  from  the  periphery  to  the 
nervous  centers  which  we  call  sensation.  Contraction  of  the 
dentinal  fibers  transmitted  into  the  reticulum  of  the  protoplasm 
at  the  periphery  of  the  pulp,  and  thence  into  the  ultimate  nerve- 
fibrillfe, — all  of  which  formations  are  proven  to  be  continuous, — 
are  suificient  to  explain  the  transmission  of  sensation,  or,  speak- 
ing bluntly,  of  pain. 

As  to  the  sensitiveness  of  enamel,  very  little  is  known.  It  is 
denied  altogether  by  E.  Baume  and  others.     ISTevertheless,  the 


PHYSIOLOGY    OF   THE    HARD    DENTAL    TISSUES.  273 

simple  experiment  of  eating  a  sour  apple  tends,  in  my  judg- 
ment, to  prove  sensitiveness  of  the  enamel.  The  sensation  which 
attends  what  is  called  "  setting  the  teeth  on  edge,"  following  in 
this  instance,  is  noticed  not  oiily  in  permanent  teeth  whose  enamel 
is  ground  oiF,  but  also  in  children  having  perfectly  sound  enamel 
upon  their  temporary  teeth.  Nobody  will  explain  this  sensation 
on  the  assumption  of  a  solution  of  the  lime-salts  of  the  enamel, 
and  a  penetration  of  the  apple's  acid  to  the  surface  of  the  den- 
tine. It  is  far  more  probable  that  the  pain  is  due  to  the  irrita- 
tion of  the  living  matter  of  normal  enamel,  and  the  transmission 
of  its  contractions  to  that  of  the  dentine,  with  which  it  is  con- 
tinuous. That  enamel,  under  morbid  conditions,  may  become 
extremely  sensitive,  is  a  fact  known  to  every  dental  practitioner. 

A  third  point  may  be  cleared  up  by  these  researches, — i.e.,  the 
discoloration  of  devitalized  teeth.  The  discoloration  concerns 
not  only  the  dentine,  but  also  the  enamel ;  indeed,  the  latter  is 
the  first  to  show  the  stain.  The  absence  of  a  nourishing  fluid, 
and  the  shrinkage  of  the  fibrillfe  of  living  matter  in  both  tissues, 
may  account  for  their  opacity  and  change  of  hue. 

The  minute  anatomy  of  the  hard  tissues  of  the  teeth,  lastly, 
throws  light  upon  the  nature  of  their  senile  changes.  In 
temporary  teeth  the  dentinal  canaliculi  are  noticeably  wider, 
and  their  tenants,  the  fibers,  larger  than  in  permanent  teeth.  In 
the  enamel-tissue  the  interstices  between  the  prisms  are  widest, 
and  their  tenants,  the  enamel-fibrillse,  largest,  in  developing  teeth, 
at  the  seventh  month  of  intra-uterine  life.  In  the  enamel  of  per- 
manent teeth  the  interprismatic  spaces  are  very  narrow,  and  their 
tenants  so  delicate  that  both  the  spaces  and  the  fibrillsB  have 
escaped  the  notice  of  previous  observers. 

With  advancing  age,  all  formations  of  living  matter  diminish 
in  bulk,  whereas  the  basis-substance,  and  the  lime-salts  held 
therein,  increase  in  amount.  This  explains  the  fact  that  the 
teeth  of  old  people  have  but  extremely  narrow  dentinal  cana- 
liculi, and  that  the  total  number  of  these  is  noticeably  lessened 
by  a  transformation  of  previous  dentinal  canaliculi  into  basis- 
substance.  This  has  been  before  proven  to  be  likewise  true  in 
the  case  of  bone-  and  cartilage-tissue,  by  Heitzmann  and  Spina. 

The  pulp-tissue  gradually  decreases  in  amount  with  advancing 
age.  This  is  due,  as  I  shall  show  in  a  future  chapter,  to  a  suc- 
cessive transformation  of  the  pulp  into  secondary  dentine. 
Nevertheless,  not  a  single  instance  is  known  of  the  complete 

19 


274  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

solidification  of  a  tooth  in  old  age,  even  thougli  the  pulp-tissue 
be  reduced  to  a  minimum,  and  the  pulp-canals  barely  accessible 
to  the  finest  broach. 

Eegardiug  the  physiology  of  the  cementum,  little  can  be  said, 
since  there  are  no  anatomical  facts  as  yet  observed  upon  which 
we  can  base  conclusions.  The  dentine  and  the  enamel  derive 
their  nutrient  material  from  the  blood-vessels  of  the  pulp.  The 
cementum  has  an  additional  source  of  nutrition  in  the  blood- 
vessels of  the  pericementum.  Should  the  pulp-tissue  perish, 
either  in  consequence  of  disease  or  of  the  application  of  arseni- 
ous  acid,  etc.,  the  dentine  and  the  enamel  become  devitalized. 
In  the  case  of  the  cementum,  devitalization  from  such  cause  is 
not  an  inevitable  result,  since  there  remains  a  possibility  of  its 
being  kept  alive  by  the  pericementum.  ISTothing  positive  has  as 
yet  been  ascertained  fixing  the  boundary  at  which  life  ends  in 
the  hard  dental  tissues. 

That  with  advancing  age  the  teeth  become  loose  and  fall  out, 
may  be  due  to  a  lack  of  nutrition  in  the  pericementum,  as  well 
as  to  a  shrinkage  of  the  sockets  in  their  transformation  into 
fibrous  connective  tissue.  Not  a  single  instance  is  known  in 
which,  with  advancing  age,  the  pericementum  ossifies,  and  the 
teeth  become  anchylosed;  but,  on  the  contrary,  in  all  instances 
they  loosen  and  are  shed. 


-       CHAPTER   XXIY. 

<JENERAL  DIAGISrOSIS  OF  THE  DISEASES  OF  THE  TEETH. 

The  line  between  normal  and  morbid  processes  in  the  tissues 
<3ainiot  always  be  distinctly  drawn.  It  is  necessary  to  be  thor- 
oughly familiar  with  the  formation  of  normal  tissues,  in  order 
to  comprehend  their  pathological  conditions.  The  formation  of 
secondary  dentine  and  bone  upon  the  wall  of  the  pulp-chamber 
of  a  tooth  can  hardly  be  called  pathological,  whereas  the  same 
formation  in  the  bod}'  of  the  pulp  often  causes  marked  disturb- 
ances. 

The  art  of  differentiation  of  diseases  is  called  "  diagnosis," 
and  the  ability  to  discern  pathological  conditions  occurring  in 
the  oral  cavity  is  the  aim  of  every  thorough  dental  practitioner. 


GENERAL    DIAGNOSIS    OF    THE    DISEASES    OF    THE    TEETH.        275 

It  is  uot  an  easy  matter  to  establish  a  correct  diagnosis  iu  every 
case  of  disease  of  the  oral  cavity.  In  some  instances  the  origin 
of  the  tronble  is  quite  obscure,  and  there  are  many  dift'erent 
diseiises  that  exhibit  almost  similar  subjective  symptoms. 

The  ability  to  diagnosticate  well  is  only  attainable  by  means 
of  a  comprehensive  knoAvledge  of  the  tissues  involved,  in  their 
normal  as  well  as  in  their  diseased  states,  and  such  a  knowl- 
edge is  only  attainable  by  experience  in  observation.  A  dental 
practitioner  who  carefully  studies  the  condition  of  his  patient 
wnll  often  be  able  to  advise  him  of  some  chronic  disorder  in  his 
(the  patient's)  system,  even  before  the  latter  has  any  knowledge 
of  it  himself.  The  teeth  and  gums,  therefore,  may  be  regarded 
as  indicators  of  the  general  health  of  their  possessor. 

In  order  to  do  this,  we  must  carefully  notice  the  color  and 
condition  of  the  gums,  the  saliva,  and  the  teeth;  the  transpar- 
ency, density,  and  sensitiveness  of  the  latter,  and  likewise  the 
consistency  of  the  calculary  deposits  around  them. 

The  tartar  being  important  in  the  diagnosis  of  constitutional 
disturbances,  I  here  will  add  a  brief  description  of  its  charac- 
teristic features. 

There  are  three  varieties  of  deposits  found  upon  the  teeth, — 
viz,  the  white,  the  yellow,  and  the  green. 

Tlie  white  deposit,  or  '-'■  materia  alba"  as  it  has  first  been 
termed  by  Leuwenhoek,  is  of  mucoid  consistenc}',  principally 
found  upon  the  labial  surfaces  of  the  ten  anterior  teeth  near  the 
gum-margin.  It  is  found  upon  loose  teeth  and  those  not  much 
used.  It  ma}^  accumulate  from  want  of  cleanliness,  or  in  con- 
stitutional disturbances.  According  to  W.  D.  Miller,*  it  con- 
sists of  epithelium,  salivary  corpuscles,  masses  of  bacteria  of 
varj'ing  sizes  and  forms,  intermixed  with  particles  of  food. 
Dependent  upon  the  constitution  and  habits  of  the  person,  this 
deposit  maybe  of  an  acid  or  alkaline  reaction,  and,  if  abundant, 
in  time  may  cause  a  chronic  inflammation  of  the  gums  and  the 
pericementum. 

Yellow  tartar  accumulates  around  the  necks  of  the  teeth  more 
or  less  in  every  mouth.  It  is  the  result  of  a  deposition  of  lime- 
salts  into  the  so-called  materia  alba.  When  first  formed,  it  is 
almost  white,  but  soon  becomes  yellowish,  whereas  the  portion 
in  contact  with  the  gum  mostly  is  of  a  darker  color,  varying 
from  a  deep  yellow  to  a  dark  brown,  or  even  black.     The  color 

"^Dental  Cosmos,  1894. 


276  THE    AXATOMY    AXD    PATH0L0C4Y    OF    THE    TEETH. 

of  this  deposit  somewhat  depends  upon  the  rapidity  with  which 
it  is  formed.  Persons  atHicted  with  rheumatism  or  gout  usually 
have  an  abundance  of  yellow  tartar,  often  collected  in  a  com- 
paratively short  space  of  time,  of  a  light  color  and  soft  consist- 
ency. The  healthier  the  person,  the  darker  is  the  hue  and  the 
harder  the  consistency  of  the  tartar.  Such  tartar  is  found 
mainly  upon  the  teeth  in  the  neighborhood  of  the  openings  of 
the  salivary  ducts.  Mastication,  especially  of  hard  substances, 
prevents  the  deposition  of  salivary  calculi  upon  the  teeth;  they 
consequently  accumulate  more  upon  that  side  of  the  mouth 
which  is  least  used. 

The  green  deposit  frequently  is  seen  upon  the  teeth  of  juveniles 
and  those  who  do.  not  clean  their  teeth  properly,  besides  in  per- 
sons who  work  in  metals  or  have  taken  metals  or  their  salts  in 
the  form  of  medicines.  It  is  found  mostly  on  the  labial  surfaces 
of  the  upper  front  teeth,  while  the  lower  ones  are  seldom 
affected.  The  color  of  the  deposit  in  juveniles  varies  from  a 
light  to  a  dark  gravish- or  bluish-sreen.  According;  to  Miller 
[l.  c),  who  was  the  first  to  give  this  matter  carefrd  attention, 
green  deposits  may  be  of  organic  or  inorganic  origin.  The  or- 
ganic stains  upon  the  teeth  are  believed  to  be  derived  from  sul- 
phomethffimogiobin  present  in  the  coloring-matter  of  the  blood, 
as  well  as  chromogenic  color-producing  bacteria.  The  discol- 
oration of  the  teeth  due  to  inorganic  substances,  according  to 
Miller,  mainly  is  produced  by  copper,  iron,  mercury,  and  lead. 

Copper  stains  are  characterized  by  a  greenish  discoloration  of 
the  labial  surfiices  of  the  teeth,  principally  those  of  the  upper 
jaw.  Together  with  this  stain,  a  red  or  greenish-brown  line  is 
sometimes  present  upon  the  gum-margin.  It  is  found  upon  the 
teeth  of  people  employed  in  the  working  of  copper  or  its  alloys. 
Occasionally  it  is  also  met  with  in  trumpeters,  where  it  arises 
from  the  contact  of  the  brass  mouth-piece  with  the  teeth. 
(Miller.) 

Iron  deposits  are  recognized  by  their  brownish  color.  (Miller.) 
They  are  found  upon  the  teeth  of  persons  working  in  iron 
factories,  and  those  who  take  iron  compounds  as  medicines. 
Iron  stains  occur  more  frequently  upon  the  lower  than  upon  the 
upper  teeth. 

The  stains  of  mercury,  when  arisen  from  its  chlorides,  are  of 
a  dark-gray  or  brownish-black  color;  while  the  sulphide  of  mer- 
cury may  cause  a  greenish  deposit.     (Miller.) 


GENERAL    DIAGNOSIS    OF    THE    DISEASES    OF    THE    TEETH.        277 

Lead,  according  to  Hirt,  produces  a  dark-brown  discoloration 
on  the  necks  of  the  teeth  of  persons  suiFering  from  lead-poison- 
ing ;  besides,  we  usually  find  the  characteristic  bluish  line  upon 
the  gums. 

It  is  believed  (Robinson,  Harris,  Leber  and  Rottenstein,  Fox 
and  Harris,  Baume,  Brandt,  Ottoleugui,  Schlenker,  etc.)  that 
the  green-stain  so  frequently  observed  upon  the  teeth  of  juveniles, 
and  those  who  do  not  clean  their  teeth  properly,  has  an  injurious 
effect  upon  the  enamel  ;  while  Miller  asserts  that  the  dissolution 
of  the  enamel  often  found  under  such  stains  is  independent  of 
the  latter.  True  it  is  that  we  often  see  the  enamel  of  the  labial 
surfaces  near  the  gum-margin  roughened  without  being  stained. 

Dark-o[rav  or  blue  and  cloudv-lookino-  enamel  on  teeth  that 
are  highly  sensitive  to  the  touch  of  an  excavator  or  bur,  indicates 
the  tendency  to  rapid  decay.  Then  the  calculary  deposits  around 
the  necks  of  such  teeth  (especially  the  lower  ones)  are  of  a  light- 
yellow  or  almost  white  color,  and  are  of  very  soft,  or  even 
slimy,  consistency.  In  many  instances  the  pulps  of  such  teeth 
are  attacked  by  pulpitis,  and  die  without  having  been  exposed. 
When  the  gums  are  soft,  and  bleed  easily,  even  at  the  lightest 
touch;  when  they  are  coated  with  viscid  mucus,  and  are  more 
or  less  detached  from  the  necks  of  the  teeth,  these,  in  general, 
are  signs  of  a  weak  constitution,  or  of  an  impaired  one. 

We  often  remark  the  rapid  destruction  of  teeth  where  there 
exists  a  diseased  condition  of  the  system,  and  with  our  best 
efforts  we  are  unable  to  save  them.  When  the  ailment  or  weak- 
ness, however,  is  of  temporary  duration,  as  in  the  state  of  preg- 
nancy, the  teeth,  as  a  rule,  return  to  the  normal  character  after 
delivery.  If  the  health  of  the  woman  is  good,  we  observe  that 
the  saliva  soon  loses  its  acidity  and  viscidity.  The  enamel  and 
the  dentine  gradually  regain  their  former  transparency  and  hard- 
ness; the  teeth  become  less  sensitive  at  their  necks,  and  the 
gums,  usually  independently  of  treatment,  are  restored  to  a 
healthy  state. 

It  is  the  rule  that  the  above-described  conditions  of  the  mouth 
are  symptomatic  in  weaklj^-constituted  persons,  yet  exceptionally 
we  remark  those  conditions  in  quite  healthy  people.  Where 
there  is  a  strong  general  constitution  in  the  possessor,  the  teeth 
are  commonly  coated  with  yellow  or  yellowish-white,  hard,  and 
transparent  enamel.     The  dentine,  as  well  as  the  cervical  mar- 


278  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

gins  of  the  necks  of  the  teeth,  are  not  very  sensitive :  the  calcu- 
lary  deposits  are  of  a  dark-brown  or  black  color,  and  of  hard 
consistency.  The  saliva  is  usually  neutral,  or  of  slightly  alkaline 
reaction,  clear  and  icatery,  not  viscid.  The  gums  are  of  pale  red 
color,  hard,  do  not  bleed  easily,  and  are  tightly  attached  to  the 
necks  of  the  teeth.  The  teeth  themselves  decay  very  slowly,  and 
the  carious  dentine  is  of  a  dark-brown  or  black  color. 

Sometimes  cavities  of  decay  in  teeth  of  this  tj'pe  are  left  ex- 
posed for  months,  or  even  years,  without  any  visible  extension, 
so  long  as  the  health  of  the  patient  remains  good.  When,  how- 
ever, through  chronic  diseases  of  the  kidneys,  liver,  or  tlie  ner- 
vous system,  the  health  of  the  patient  fails,  we  soon  begin  to 
notice  a  marked  change  in  the  tissues  of  the  teeth  and  of  their 
surroundings,  though  the  patient,  as  we  intimated  before,  is 
perhaps  unaware  of  his  ailment. 

The  first  visible  changes,  in  such  a  case,  take  place  in  the 
gum  around  the  necks  of  the  teeth,  especially  of  the  lower 
incisors.  Where  three  or  six  months  ago  we  observed  hard 
gums,  of  a  pale  rosy  color,  and  tightly  encircling  the  necks 
of  the  teeth,  we  now  see  on  the  gum  a  dark-red  or  perhaps  a 
bluish  band,  indicative  of  the  early  stages  of  pyorrhoea  alveo- 
laris.  The  salivary  calculus,  formerly  quite  hard,  of  a  brownish 
color  and  of  slow  accumulation,  appears  now  as  a  yellowish- 
white,  creamy  deposit,  and  more  profusely,  especially  at  the  necks 
of  the  affected  teeth.  With  the  advance  of  the  systemic  diseaf-e 
progresses  the  caries  of  the  teeth,  the  carious  matter  being  now 
of  a  light-yellow  color,  or  white,  while  the  teeth  become  ex- 
tremely sensitive,  not  only  to  the  touch  of  excavating  instru- 
ments, but  even  to  thermal  changes.  The  saliva  is  quite  viscid, 
and  of  a  distinct  acid  reaction. 

The  teeth  under  these  conditions  soon  lose  their  normal  color 
and  transparency,  become  brownish,  bluish,  or  greenish,  and  the 
enamel  and  dentine  are  extremely  soft.  The  pulps  die  readily, 
sometimes  without  pain,  and  frequently  are  found  to  produce 
alveolar  abscesses,  and  extensive  necrosis,  or  cystic  formations  in 
the  jaws.  When  such  signs  of  a  decline  in  the  normal  standard 
of  health  in  the  oral  cavity  are  remaiked  in  a  patient  whom  we 
have  known  for  years,  the  prognosis  is  usually  alarming.  In 
order  to  make  clear  what  I  have  stated,  I  shall  cite  two  typical 
cases  of  my  practice. 

Mr.  W.,  about  forty-five  years  of  age,  of  an  excellent  consti- 


GENERAL    DIAGNOSIS    OF    THE    DISEASES    OF    THE    TEETH.        279 

tution,  consulted  me  in  Xovember,  1880,  in  regard  to  the  restora- 
tion of  the  lingual  surfaces  and  cutting-edges  of  his  remaining 
five  upper  front  teeth,  and  the  laljial  surfaces  and  cutting-edges 
of  the  ten  lower  front  teeth.  The  teeth  were  of  a  yellowish-white 
color,  with  exceedingly  hard  enamel  and  dentine.  The  left 
upper  second  molar  had  been  carious  over  twelve  years,-  but 
as  some  one  had  advised  Mr.  W.  to  have  the  tooth  extracted 
rather  than  filled,  he  had  allowed  it  to  remain  in  that  condition. 
The  color  of  the  carious  dentine  of  this  tooth  was  brownish- 
black,  and  it  was  almost  as  hard  as  enamel,  while  the  pulp  was 
found  to  be  dead.  The  fifteen  front  teeth  were  restored  with  gold 
to  their  normal  length,  while  the  three  canals  and  the  cavity  of 
the  second  upper  molar  were  filled  with  oxy chloride  of  zinc. 
Those  teeth  were  quite  comfortable  till  October,  1888,  when  the 
lower  teeth  began  to  exhibit  the  synjptoms  of  pyorrhoea  alveolaris, 
and  the  left  upper  lateral  incisor,  during  a  period  of  four  months, 
had  changed  in  color  to  a  dark  blue.  When  the  pulp-chamber 
was  opened,  a  great  quantity  of  pus  was  discharged  from  the 
socket,  through  the  tooth,  denoting  the  presence  of  a  chronic 
alveolar  abscess  and  necrosis.  On  examination  of  the  other 
teeth,  it  was  found  that  most  of  them  were  decayed  around  the 
necks,  while  the  second  upper  molar  was  altogether  broken 
down. 

The  carious  portion  of  the  dentine  was  now  exceedingly  soft, 
and  the  necks  of  the  teeth  were  covered  by  a  yellowish-white 
mucoid  deposit,  quite  acid  in  reaction.  In  response  to  my  query 
as  to  the  gentleman's  health,  he  replied  that  he  had  never  felt 
better  in  his  life.  I  advised  his  family  to  inform  his  physician 
that  I  had  grave  suspicions  regarding  Mr.  W.'s  general  health. 
An  external  examination  was  made,  without  an  analysis  of  the 
urine,  and  no  serious  danger  was  reported. 

In  time  the  teeth  of  the  patient  were  destroyed;  some  of  the 
lower  incisors  falling  out  in  consequence  of  pyorrhoea  alveolaris, 
while  others  lost  their  crowns  through  caries.  In  October,  1893, 
he  died  of  chronic  parenchymatous  nephritis  (Bright's  disease 
of  the  kidneys),  though  there  had  been  no  previous  warning  of 
his  illness  beyond  that  which  I  have  described. 

Miss  P.,  about  eighteen  years  of  age,  with  a  good  constitution, 
was  the  possessor  of  an  almost  perfect  set  of  teeth,  except  that 
upon  the  grinding-surfaces  of  the  four  first  permanent  molars 
the  enamel  was  not  perfectly  calcified.     The  grinding-surfaces  of 


280  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

these  four  teeth  were  restored  with  gold,  in  October,  1887.  The 
other  teeth  were  of  a  bluish-white  color,  quite  hard,  and  but 
little  sensitive  to  excavation.  The  mouth,  as  well  as  the  face  of 
the  patient,  at  that  time,  presented  a  typically  healthy  appear- 
ence.  I  saw  her  in  June,  1888,  May,  1890,  June,  1891,  when  I 
filled  only  ordinary  cavities  in  the  grinding-surfaces  of  the  teeth, 
which  up  to  that  time  were  in  a  normal  condition.  I  saw  the 
patient  again  in  March,  1892,  when  I  noticed  a  great  change  in 
her  dentures,  gums,  and  saliva,  as  well  as  in  her  general  coun- 
tenance. The  face  had  changed  to  a  pale  grayish  hue;  the  eyes 
had  lost  their  former  brightness;  the  teeth  were  quite  soft,  very 
sensitive,  and  of  a  dark-blue  tint.  The  gums  were  light  pink, 
except  around  the  lower  incisor  teeth,  where  I  noticed  a  slight 
inflammation.  The  saliva,  although  watery,  had  a  distinct  acid 
reaction.  Upon  examination,  I  found  five  large  carious  cavities 
in  the  teeth,  the  dentine  of  which,  in  the  process  of  excavating, 
proved  to  be  exceedingly  soft  and  sensitive.  Upon  the  query  as 
to  the  state  of  her  general  health,  she  replied  that  she  was  as 
well  as  ever.  I  advised  the  patient  to  see  her  physician  in  re- 
gard to  her  general  condition,  but  she  did  not  think  it  necessary, 
the  more  so  as  she  intended  to  leave  for  Europe  in  about  ten 
days.  Shortly  before  her  departure  she  did  not  feel  quite  well, 
when  her  physician  was  consulted,  who  announced  that  she  was 
suffering  from  a  severe  disease  of  the  nervous  system,  Basedow's 
or  Graves's  disease,  to-day  termed  exophthalmic  goitre. 

In  the  diagnosis  of  the  diseases  of  the  mouth,  we  must  care- 
fully consider  : 

First.  The  individual  characteristics  of  the  patient,  the  nor- 
mal' standard  of  his  or  her  health,  and  ascertain,  if  possible, 
whether  the  system  is  deranged  by  temporary  or  constitutional 
disturbances,  such  as  menstruation,  pregnancy,  ausemia,  chronic 
diseases  of  the  nervous  system,  of  the  liver,  or  of  the  kidneys, 
the  effects  of  external  or  hereditary  influence,  etc. 

Second.  Pathological  phenomena  in  distant  parts,  resulting 
from  reflex  action  of  irritated  nerves. 

Third.  The  minute  anatomy  of  the  immediately  involved 
parts,  and  the  laws  governing  their  progressive  as  well  as  retro- 
g;ressive  changes. 

Fourth.  The  observations  of  our  senses,  in  physical  exam- 
ination, in  the  use  of  instruments,  or  by  other  methods. 


GENERAL    DIAGNOSIS    OF    THE    DISEASES    OF    THE    TEETH.        281 

Fifth.  The  subjective  symptoms  which  are  the  local  or  gen- 
eral phenomena  of  the  disease,  as  noticed  by  the  patient  himself. 

Sixth.  The  difterential  diagnosis,  which  is  the  consideration 
of  the  features  that  distinguish  one  disease  from  another  dis- 
ease, when  there  are  like  symptoms  in  both. 

The  prognosis  consists  of  the  conckisions  arrived  at  in  a  sum- 
ming up  of  all  the  above-intimated  phenomena,  collectively 
considered. 

In  physical  examination  of  the  diseases  of  the  oral  cavity,  we 
employ,  besides  our  sense  of  sight,  the  senses  of  touch,  hearing, 
and  smell;  sometimes,  also,  light,  percussion,  heat,  and  cold. 

At  sight  we  are,  in  many  cases,  enabled  to  determine  the 
general  state  of  a  patient's  health.  Before  making  a  physical 
examination  of  the  oral  cavity,  we  ought  to  observe  the  shape, 
color,  and  expression  of  the  patient's  face  and  eyes,  as  well  as 
his  general  countenance.  To  l)e  able  to  see  the  differences  of 
the  normal  tissues  of  the  oral  cavity  from  those  that  are  dis- 
eased, we  must  become  familiar  with  their  normal  appearance. 
We  should  study  the  normal  color  and  aspect  of  the  gums  and 
tongue  of  persons  of  different  constitutions.  TTe  shall  then  be 
able  to  discover  conditions  of  inflammation  in  the  oral  ca^dty, 
even  where  these  are  slightly  indicated,  recognizing  them  by 
the  mere  difference  in  color  which  the  inflamed  mucous  mem- 
brane exhibits  in  contrast  to  the  normal  one. 

The  sense  of  touch  is  of  great  importance,  and  is  one  that 
ought  to  be  cultivated  to  perfection  by  every  dental  student.  It 
is  employed  either  directly  at  the  point  of  the  index  finger,  or 
indirectly  by  means  of  a  probe  or  any  other  instrument.  In 
most  cases  of  pericementitis  and  periostitis  we  are  enabled  to 
ascertain  by  means  of  the  index  finger  to  what  degree  the  in- 
ffammatory  process  has  advanced.  In  a  physical  examination 
we  should  always  compare  the  diseased  part  of  the  oral  cavity 
w^ith  the  corresponding  usualh'  normal  portion  of  the  opposite 
side.  In  this  investigation  the  finger  will  easily  find  whether 
or  not  there  exists  a  swelling  on  the  gums,  which  portion  is 
hard,  unyielding,  and  of  normal  temperature,  or  soft,  hot,  and 
fluctuating.  More  important,  however,  than  the  examination 
by  the  point  of  the  finger,  is  that  which  exercises  the  sense  of 
touch  through  the  medium  of  an  instrument.  This  can  be  de- 
veloped to  accuracy  only  by  ample  practice.  We  may  train  our 
sense  of  touch  to  such  perfection  that  we  become  able  to  differ- 


282  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

entiate  between  all  tissues  with  which  the  probe  comes  in  con- 
tact, determining  whether  the  substance  touched  be  soft  tissue. 
or  enamel,  or  dentine,  compact  or  cancellous  bone;  distinguish- 
ing also  whether  the  latter  tissue  be  living  or  necrotic,  and  dis- 
criminating from  one  another  steel,  gold,  amalgam,  etc.,  when 
they  are  hidden  from  view. 

The  most  frequent  examination  of  the  dental  practitioner  is 
the  search  of  the  teeth  for  carious  cavities.  In  many  instances 
these  are  easily  found.  There  are  patients  who  experience  pain 
as  soon  as  a  small  cavity  exists,  which  may  hardly  have  pene- 
trated the  interzonal  layer.  In  other  instances  we  encounter 
patients  who  have  many  cavities,  and  the  teeth  in  many  places 
broken  down,  and  who,  notwithstanding,  have  never  complained 
of  toothache.  In  the  latter  cases,  examination  should  be  made 
carefully  on  all  surfaces  of  the  teeth;  whereas,  in  an  instance  of 
the  former  description,  the  patient  himself  may  designate  the 
locality  of  the  caries. 

In  examining  the  teeth  for  caries,  we  employ  a  mouth-mirror 
and  a  delicate  steel  exploring  instrument.  The  teeth  frequently 
decay  on  their  approximal  surfaces;  and  where  they  stand  so 
close  together  that  we  cannot  penetrate  the  interstices  even  with 
the  finest  broach,  it  becomes  difficult  to  determine  whether  or 
not  the  tooth  contains  a  carious  cavity.  In  the  majority  of 
teeth  decayed  on  the  approximal  surface,  the  cavity  may  be 
detected  in  the  incisors,  the  cuspids,  and  the  bicuspids  bj^  a 
bluish  line  on  the  respective  labial  or  buccal  surfaces,  when 
concentrated  daylight  or  electric  light  is  thrown  under  the 
lingual  surfaces.  AVhen  a  carious  cavity  is  small,  however,  we 
may  fail  to  detect  it  even  by  transillumination  of  the  teeth.  In 
such  a  case  we  are  obliged  to  separate  the  teeth  slightly,  either 
at  once  by  a  screw  separator,  or  gradually  by  cotton  or  wood 
wedges  or  other  suitable  means. 

Examination  of  the  teeth  should  always  be  systematic.  We 
ought  to  begin,  regularly,  with  the  last  molar,  either  of  the  upper 
or  the  lower  jaw.  In  examining  a  single  tooth,  much  may  be 
overlooked, — perhaps  even  the  seat  of  the  trouble,  since  it  fre- 
quently happens,  where  two  or  three  teeth  are  decayed  on  the 
same  side  of  the  mouth,  that  the  patient  attributes  the  pain  to  a 
wrong  tooth.  The  grinding-surfaces  of  the  teeth  should  be  first 
carefully  explored,  then  the  approximal,  next  the  buccal,  respec- 
tively labial  and  lingual  surfaces,  and  at  last  the  necks  slightly 


GENERAL    DIAGNOSIS    OF    THE    DISEASES    OF    THE    TEETH.        28S 

bej'ond  the  gums.  For  the  latter  purpose,  it  is  advisable  to  re- 
peatedly moisten  the  exploring  instrument  with  a  solution  of 
corrosive  sublimate,  1  to  1000,  although  the  instrument  may 
have  been  thoroughl}^  sterilized  before.  The  exploring  instru- 
ment should  be  handled  very  delicately  between  the  thumb  and 
the  first  two  fingers,  somewhat  like  a  pen  in  writing.  The  in- 
strument should  be  moved  along  the  surfaces  of  the  teeth  mainly 
by  the  muscles  of  the  fingers,  whereas  the  joint  at  the  wrist 
ought  to  be  employed  but  exceptionally.  When  a  cavity  is  deep, 
and  we  expect  to  find  the  pulp  of  the  tooth  exposed,  it  is  desir- 
able to  exert  a  slight  pressure  in  the  region  of  the  pulp,  a  small 
piece  of  cotton  making  a  satisfactory  interposition.  Xo  pointed 
instrument  should  be  introduced  into  a  deep  carious  cavity  in 
the  vicinity  of  the  pulp. 

If  the  patient  feels  no  pain  upon  slight  pressure  with  cotton, 
this  means  that  the  pulp  is  either  not  exposed  or  is  partially  or 
wholly  devitalized.  In  every  instance  of  deep-seated  caries  it  is 
advisable  to  remove  the  decayed  dentine  by  as  large  an  exca- 
vator or  round  bur  as  the  cavit}'  will  admit.  Small  instruments, 
by  perforating  the  protecting  thin  layer  of  dentine,  are  likely  to 
enter  a  healthy  pulp,  and  besides  causing  severe  pain  to  the 
patient,  may  produce  acute  pulpitis,  which  is  likely  to  cause  ihe 
death  of  the  pulp. 

Percussion. — When  the  hammer  of  a  piano  is  thrown  against 
one  of  the  expanded  wires,  it  causes  the  wire  to  vibrate  and 
produce  a  sound.  Similarly,  if  w^e  slightly  hammer  with  an  in- 
strument upon  a  normal  tooth,  we  cause  the  tooth  and  its  sur- 
rounding tissue  to  vibrate  and  produce  a  sound,  which,  however, 
in  duration  and  resonance  cannot  be  compared  with  that  pro- 
duced by  the  string  of  the  piano. 

In  the  practice  of  medicine,  the  diagnosis  of  some  of  the 
diseases  of  internal  organs  is  based  upon  sounds,  produced  by 
hammering  upon  the  external  surface  of  the  body  under  which 
the  diseased  organ  is  situated.  The  latter,  according  to  its  con- 
sistency and  condition,  upon  percussion,  renders  back  a  resonance 
characteristic  of  the  organ  when  normal.  In  its  pathological 
conditions  the  sounds  it  returns  in  percussion  are  materially 
altered  from  those  of  the  normal  state.  In  dental  practice, 
slight  percussion  upon  the  teeth  by  means  of  the  point  of  a 
finger,  or  wath  an  instrument,  aids  us  to  arrive  at  a  diagnosis  of 
some  of  the  forms  of  pulpitis  and  pericementitis.     Especially  in 


284:  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

cases  of  pericementitis  in  its  earliest  stages,  often  when  the 
patient  as  yet  has  felt  no  pain  nor  discomfort  in  the  affected 
tooth,  we  shall  be  able  to  notice,  upon  percussion  of  the  tooth, 
a  sound  somewhat  duller  than  the  normal;  while  its  neighbor, 
or  its  fellow  on  the  opposite  side  of  the  mouth,  upon  percussion, 
produces  a  normal  sound.  In  comparing  the  resonance  of  a 
tooth  with  that  of  its  neighbor,  or  that  of  a  tooth  on  the  oppo- 
site side  of  the  mouth,  care  must  be  exercised  to  strike  similar 
teeth  in  the  same  direction.  For  satisfactory  results  much 
depends  also  upon  the  position  of  the  tongue,  the  lips,  and  the 
lower  jaw.  If  the  mouth  is  wide  open,  the  resonance  of  the 
teeth  will  be  higher  in  pitch  than  when  the  mouth  is  nearly 
closed.  In  percussion  of  the  teeth,  we  notice  five  difierent 
sounds, — viz,  the  high,  the  loic,  the  clear,  and  the  dull,  as  well  as 
a  somewhat  t'/mpanitic  sound.  When  the  mouth  is  wide  open,  we 
obtain  the  high  sound ;  when  nearly  closed,  the  low  one.  When 
we  hammer  slightly  upon  the  crown  of  a  normal  tooth,  we 
obtain  a  clear  sound.  If,  on  the  contrary,  percussion  is  made 
upon  a  tooth  which  in  the  process  of  pericementitis  has  become 
loosened  in  its  socket,  we  shall  perceive  a  distinct  dull  sound. 
A  somewhat  tympanitic  sound  is  produced  by  percussion  upon 
the  second  upper  bicuspid,  still  more  pronounced  in  the  first 
molar  of  the  upper  jaw. 

In  physical  examination,  we  also  have  to  consider  the  general 
condition  of  all  the  teeth  in  the  mouth.  •  The  teeth  of  some 
patients,  upon  percussion,  always  give  out  a  dull  sound.  These 
teeth  usualW  are  somewhat  loose  in  their  sockets,  although 
their  pericementum  appears  normal.  Such  patients  may  be 
young  or  in  the  prime  of  life,  whereas  we  meet  with  persons 
quite  old  whose  teeth,  firm  in  their  sockets,  produce  a  clear 
sound  on  percussion.  "We  have  to  take  into  consideration, 
also,  the  number  of  roots  which  the  tooth  possesses.  As  a 
general  rule,  we  find  that  a  tooth  with  two  roots  gives  out, 
on  percussion,  a  sound  a  trifle  clearer  than  does  a  tooth  of  but 
one  root,  while  the  upper  molars  give  the  clearest  sound  of  all. 
Therefore,  in  making,  by  means  of  percussion,  a  diagnosis  as  to 
a  bicuspid  or  molar  tooth,  it  is  advisable  to  compare  its  sound 
with  that  of  the  corresponding  tooth  on  the  opposite  side  of  the 
mouth.  The  six  anterior  teeth  of  the  upper  jaw,  if  normal, 
yield,  on  percussion,  sounds  nearly  equal  in .  clearness.  There 
is,  however,  sometimes  a  slight  difierence  in  the  sounds  rendered 


GENERAL    DIAGNOSIS    OF    THE    DISEASES    OF    THE    TEETH.        285' 

by  the  upper  incisors  from  those  of  the  cuspids,  a  difference 
probably  due  to  the  length  of  the  roots.  In  a  series  of  percus- 
sions from  the  first  upper  bicuspid  to  the  second  upper  molar, 
we  notice  a  gradual  increase  in  the  pitch  of  the  sound,  due  to 
the  existence  of  the  antrum,  which,  being  filled  Avith  air  and 
comraunicating  with  the  nasal  cavities,  causes  a  more  or  less 
tympanitic  resonance. 

Although,  as  in  cases  of  hyperostosis  of  the  roots,  the  sounds 
produced  by  percussion  on  the  corresponding  teeth  of  opposite 
sides  of  the  mouth  are  not  always  identical,  yet,  with  experi- 
ence, we  will  soon  be  able  to  differentiate  between  the  sounds 
of  a  tooth  with  a  normal,  and  of  a  tooth  with  an  inflamfed,  peri- 
cementum. In  cases  of  slight  circumscribed  pericementitis,  we 
are  often  enabled  to  localize  the  inflamed  portion  in  the  peri- 
cementum, unless  this  be  situated  on  the  mesial  or  the  distal 
surface  of  the  root,  and  unless  the  crowns  of  the  teeth  stand 
in  close  contact  with  those  of  their  neighbors.  Percussion 
upon  the  crown  of  a  tooth  in  the  direction  of  the  inflamed  spot 
will  produce  a  somewhat  dull  sound.  Therefore,  if  pericemen- 
titis is  seated  in  the  lingual  portion  of  the  root  of  the  toothy 
slight  percussion  upon  the  labial,  respectively  buccal  surface  of 
the  crown,  in  the  direction  of  the  inflammation,  will  produce  a 
duller  sound  than  that  evoked  when,  by  the  same  instrument, 
the  tooth  is  tapped  on  the  lingual  surface.  If,  on  the  contrary, 
pericementitis  is  seated  in  the  apex  of  the  root,  percussion  in 
that  direction  upon  the  crown  of  the  tooth  will  evoke  the  char- 
acteristic dull  sound.  In  this  manner  we  are  often  enabled  to 
ascertain  which  of  the  roots  of  a  molar  or  first  bicuspid  tooth 
is  inflamed.  The  degree  of  the  dullness  of  the  sound  depends 
upon  the  degree  of  the  inflammatory  condition  of  the  perice- 
mentum. Therefore,  the  more  diffused  the  inflammation  around 
the  root  of  the  tooth,  the  duller  will  be  the  sound  and  the  greater 
the  sensitiveness  on  percussion.  Thus  the  character  of  the 
sound  produced  by  percussion  of  the  teeth  principally  depends 
upon  the  continuity,  the  elasticity,  and  the  surroundings  of  the 
vibrating  tissue.  In  more  advanced  stages  of  pericementitis,  on 
percussion  of  the  affected  tooth,  we  notice,  besides  a  distinct  dull- 
ness in  sound,  sensitiveness  or  pain,  increasing  in  severity  with 
the  advance  of  the  inflammatory  process  of  the  pericementum. 

By  our  sense  of  smell  we  detect  septic  conditions  of  the  oral 
cavity,  especially  in  diseases  of  the  antrum  and  the  pulp.     In 


'2S6  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

order  to  arrive  at  a  proper  diagnosis,  it  is  necessarj  to  be 
acquainted  with  the  peculiar  odors  characteristic  of  an  inflamed 
condition  of  the  antrum,  as  well  as  of  gangrene  of  the  pulp. 
There  is,  also,  in  the  breath  of  some  patients,  a  peculiar  sweetish 
odor,  which  somewhat  resembles  that  of  chloroform,  and  is 
<3haracteristic  of  a  febrile  or  otherwise  diseased  state  of  the 
system.  All  these  peculiarities  should  be  carefully  noticed,  as 
sometimes  they  may  aid  us  in  makino-  a  dias^nosis. 

In  diagnosticating  pathological  conditions  of  the  pulps  of  the 
teeth,  we  also  employ  the  agencies  of  heat  and  cold,  by  means 
of  water,  air,  or  the  spray  of  the  chloride  of  methyl.  Extreme 
cold,  directed  suddenly  to  the  tissues,  produces  local  anesthesia, 
as  is  observed  in  the  application  of  the  chloride-of-methyl  spray. 
Extreme  heat  has  the  same  effect  as  extreme  cold,  causing  irri- 
tation and  death  when  its  operation  is  persistent.  Thermal 
changes  wrought  suddenly  on  the  tissues,  especially  those  of  the 
teeth,  induce  pain  by  causing  rapid  contraction  or  expansion  of 
the  lining  matter.  In  thermal  change,  however,  not  suddenly 
produced,  but  wrought  by  mild  degrees,  heat  has  the  oppo- 
site effect  on  the  tissues  to  that  of  cold.  In  general,  heat  fayors 
activity  in  the  circulation,  while  cold  depresses  it.  The  con- 
tinued application  of  heat,  therefore,  induces  an  engorgement  of 
the  capillaries,  at  the  same  time  diminishing  the  quantity  of 
blood  in  the  larger  vessels,  as  well  as  in  internal  organs.  The 
continuous  application  of  moderate  cold  to  the  tissues  induces  a 
contraction  of  the  smaller  arteries,  and  thereby  diminishes  the 
quantity  of  blood.  The  blood-vessels  are  under  the  control  of 
the  vaso-motor  neryes.  Anything,  therefore,  which  stimulates 
or  depresses  the  nerves,  affects  the  blood-supply  in  the  region  of 
the  affected  vaso-motor  nerve.  In  the  diagnosis  of  chronic 
pulpitis,  the  application  of  heat  and  cold  is  sometimes  the  only 
trustworthy  means  of  finding  the  seat  of  ailment.  In  many 
instances,  as  I  shall  show  in  a  later  chapter,  the  patient  localizes 
in  one  part  the  pain  which  really  belongs  elsewhere.  A  sudden 
application,  through  a  syringe,  of  cold  air  or  ice-water,  or  of  hot 
air  or  hot  water,  to  the  unaffected  teeth  and  to  the  affected  tooth, 
as  a  rule,  speedily  defines  the  locality  of  the  disease;  the  response 
of  intensified  pain  following  the  injection  into  the  actually  dis- 
eased quarter.  Care,  however,  should  be  taken  that  but  one  or  two 
teeth  be  brought  under  the  direct  action  of  the  heat  or  cold,  a  pre- 
caution which  the  practitioner  carries  out  by  covering  the  other 


GENERAL    DIAGNOSIS    OF    THE    DISEASES    OF    THE    TEETH.        287 

teeth  tightly  with  bibulous  paper  or  a  napkin,  and  removing, 
with  a  saliva-ejector,  the  hot  or  cold  water  that  has  been  used.  In 
<?ases  of  a  doubtful  diagnosis  as  to  the  vitalit\'  or  deadness  of  a 
tooth,  the  application  of  the  chloride-of-methyl  spray  is  the  best 
means  of  determining  the  fact.  Applied  to  a  living  tooth,  it 
causes  pain ;  to  a  devitalized  tooth  the  application  is  painless. 

Liqhi,  either  plain  or  augmented,  or  by  appliances  of  art,  is 
anottier  agent  which  we  frequently  employ  in  diagnosticating 
■diseases  of  the  antrum,  also  in  ascertaining  whether  the  pulp'  of 
a  tooth  is  dead  or  alive,  and  in  the  search  for  carious  cavities. 

In  1881,  Louis  Elsberg,  in  an  address  before  the  Odontologi- 
cal  Society  of  Xew  York,  explained  the  manner  in  which  at 
that  time  he  was  accustomed  to  illuminate  the  mouth  and  larynx 
by  means  of  Trouve's  apparatus.  This  exposition  of  his  pro- 
cedure did  much  to  further  the  improvement  of  the  method, 
and  to  bring  to  perfection  the  illuminating  apparatus  now  in 
use.  The  process  commonly  followed  has  been  called  "  trans- 
illumination" by  W.  Freudenthal,  who  gives  a  good  description 
of  it  in  a  paper  read  before  the  Xew  York  Academy  of  Medi- 
cine, in  1891.  The  instrument  most  effectiyely  employed  is  a 
small  electric  lamp  placed  under  the  hard  palate,  in  the  patient's 
mouth,  which  should  be  closed  as  nearly  as  possible.  The  lamp 
will  then  illuminate  the  whole  middle  region  of  the  patient's 
face,  and  even  the  ej'es.  When  both  antra  are  in  a  normal  con- 
dition, the  illumination  is  uniform  on  both  sides  of  the  face.  If, 
on  the  contrary,  there  is  in  one  of  the  antra  an  abnormal  growth, 
or  merely  a  thickening  of  the  lining  membrane,  the  light-rays 
are  obstructed,  and  according  to  the  extent  of  the  obstructing 
tissue  will  the  affected  part  be  less  illuminated,  or  altogether 
dark.  The  same  process  may  be  effectively  pursued  in  the  ex- 
amination of  devitalized  or  carious  teeth.  To  this  end  the  lamp 
is  held  as  in  the  former  inspection,  the  patient's  jaws  being  nearly 
closed,  but  the  lips  kept  open.  In  such  illumination  devitalized 
teeth  appear  opaque,  while  the  teeth  with  living  pulps  are  quite 
transparent.  In  some  instances  the  teeth  stand  so  close  together 
in  the  dental  arch  that  we  are  unable,  even  with  the  finest  broach, 
to  search  their  joined  surfaces  for  carious  cavities.  In  this  case 
transillumination  is  especially  employed  with  advantage  upon 
the  ten  or  twelve  anterior  teeth.  Cavities  that  exist  in  the  jux- 
taposed surfaces  of  these  teeth  obstruct  the  light-rays  and  show 
corresponding  dark  spots. 


.288  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

CHAPTER  XXY. 

IRRITATION  AND  NEAV  FORMATIONS  OF  DENTAL  TISSUE. 

In  the  chapter  on  the  physiology  of  the  teeth  I  have  indicated 
the  manner  in  which  sensation  is  carried  from  the  surface  of  the 
enamel  and  of  the  dentine  to  the  pulp;  viz,  that  this  is  very 
probably  accomplished  by  the  alternate  contractions  and  expan- 
sions of  the  living  matter,  and  that  intense  contractions  induced 
by  highly  irritating  agencies  result  in  the  sensation  of  pain.  We 
may  admit  as  a  fact  the  existence  of  contractions  in  the  living 
matter  in  such  slight  degree  as  not  only  to  be  painless,  but  even 
devoid  of  unpleasant  sensations. 

Such  slight  contractions,  if  continuous,  are  what  clinicians 
term  "irritation."  Continuous,  though  slight,  contractions  of 
the  living  matter,  conveyed  from  the  periphery  to  the  center  of 
a  tooth,  may  suffice  directly  to  excite  contractions  of  the  living 
matter  of  the  pulp-tissue,  and,  indirectly,  through  reflex  action, 
to  influence  the  vaso-motor  nerves  of  a  limited  region  of  the 
blood-vessels  of  the  pulp-tissue. 

In  either  case,  we  may  infer  an  increased  afflux  of  nourishing 
material  to  the  irritated  part,  in  which  a  morbid  process  takes 
place,  which,  naturally,  becomes  more  evident  when  it  reaches 
the  stage  of  inflammation.  The  first  change  in  the  afiected 
tissue  is  its  reduction  to  an  embryonal  or  protoplasmic  state. 
The  pulp-tissue  is  made  up  of  a  myxomatous  tissue  holding  but 
little  basis-substance, — a  characteristic  embryonal  condition. 
The  presence  of  small  globular  lumps  of  nearly  homogeneous 
living  matter,  scattered  through  the  basis-substance,  and  closely 
resembling  lymph-corpuscles,  has  induced  previous  observers  to 
term  the  pulp-tissue  an  "adenoid  tissue,"  since  the  lymph-gan- 
glia, throughout  the  animal  body  in  general,  are  constructed  on 
the  type  of  pulp-tissue.  The  lymph-ganglia  w^ere,  some  forty 
years  ago,  considered  as  glands ;  and  they,  and  the  lymph-fol- 
licles as  well,  were  called,  accordingly,  "lymph-glands."  This 
error  was  committed  mainly  by  German  histologists,  headed  by 
E.  Brlicke.  To-day  w^e  know  that  the  lymph-ganglia  are  strictly 
connective-tissue  formations,  lacking  epithelia,  the  essential 
secreting  constituent  of  a  gland.  Hence  the  terms  "  lymph- 
gland"  and  "  adenoid  tissue,"  which  convey  the  idea  of  a  gland- 
like structure,  have  been  justly  abandoned;  and,  to-day,  reject- 


IREITATIOX    AND    NEW    FORMATIONS    OF    DENTAL    TISSUE.       289 

ing  the  word  "  adenoid"  with  its  misleading  significance,  we 
speak  of  a  "  lymph-tissue,"  which  we  know  to  be  myxomatous. 

Should  the  l3^mph-tissue  of  the  pulp  be  reduced  to  its  embry- 
onal condition  as  above  indicated,  the  protoplasm  present  before 
transformation  into  myxomatous  basis-substance  reappears,  and 
may  break  up  either  into  odontoblasts  or  into  osteoblasts.  In 
the  former  case,  the  result  of  irritation  of  the  pulp-tissue  will 
be  dentine  ;  in  the  latter,  hone. 

Odontoblasts  are  known  to  be  a  fore-stage  in  the  production  of 
dentine.  If  these  appear  in  consequence  of  irritation,  they  are 
never  so  regular  as  those  of  primary,  well-developed  dentine. 
Before  eburnification  the  odontoblasts  must  break  up  into  rows 
or  clusters  of  indifferent  or  medullary  corpuscles,  all  intercon- 
nected by  means  of  delicate  threads  of  li^dng  matter.  From 
these  threads  arise,  as  a  result  of  the  coalescence  of  the  inter- 
connecting threads,  coarser  fibrillse  of  living  matter,  the  future 
dentinal  fibers. 

The  original  odontoblasts  and  their  derivations,  the  embryonal 
corpuscles,  being  irregular  in  shape  and  unevenly  distributed 
and  grouped,  will,  in  turn,  produce  a  dentine  irregular  in  struc- 
ture, scantily  pro\dded  with  dentinal  fibers,  and  often  stratified. 
Such  dentine  we  term  secondary  dentine. 

If  osteoblasts  have  been  the  outcome  of  the  structural  change 
of  the  pulp-tissue,  these  osteoblasts,  again,  will  break  up  into 
embryonal  corpuscles,  but,  after  accomplished  calcification  of 
the  basis-substance,  they  will  produce  bone-tissue.  The  lime- 
salts  necessary  for  the  production  of  secondary  dentine  or 
osseous  tissue  are,  doubtless,  supplied  by  the  capillary  blood- 
vessels, from  the  serum  of  the  blood  circulating  therein.  It  is 
possible  that  the  capillaries  traversing  difi^erent  organs  of  the 
animal  body  hold  chemically  dififerent  contents.  The  eclectic 
power  by  means  of  which  the  contents  of  the  capillaries  are 
drawn  into  the  permeated  tissues,  rests,  very  probably,  in  the 
endothelial  walls.  Thus  the  endothelia  of  the  capillaries  of  the 
pulp  are  fitted  mainly  for  the  emission  of  a  serum  rich  in  lime 
solutions,  though  many  capillaries  in  the  irritated  part  are  known 
to  perish,  becoming  obliterated,  solidified,  and  broken  up  into 
embryonal  tissue. 

The  so-called  pulp-stones  are  nothing  but  secondary  dentine 
or  secondary  bone,  either  sessile,  i.e.,  attached  broadly  to  the 
wall  of  the  dentine,  or  pediculated,  i.e.,  attached  to  the  dentinal 

20 


290      THE  ANATOMY  AND  PATHOLO*!!'  OF  THE  TEETH. 

wall  bv  a  comparatively  narrow  foot ;  or,  lastly,  isolated  in  the 
pulp-tissue,  lacking  attachment  altogether.  C.  "Wecll  has  an- 
nounced the  theory  that  pulp-stones  are  the  result  of  an  involu- 
tion or  reduplication  of  the  odontoblast  layer  of  the  pulp, 
directed  from  the  periphery  into  the  center.  This  view  is 
marred  by  the  fact  that  the  pulp-tissue,  if  irritated,  is  capable 
of  producing  odontoblasts  as  well  as  osteoblasts,  in  any  part  of 
it.  To  me  it  seems  that  merel}^  a  slight  and  steady  irritation  of 
a  certain  portion  of  the  pulp  is  sufficient  for  the  production  of 
pulp-stones,  either  of  a  dentinal  or  of  a  bony  type,  or,  as  may 
occur,  a  mixture  of  both. 

I  have  stated  before  that  the  formation  of  secondary  dentine 
or  secondary  bone  from  the  pulp-tissue  is  the  result  of  a  slight, 
though  incessant,  irritation  of  this  tissue,  frequentl}^  unper- 
ceived  by  the  person  affected.  It  does  not,  however,  invariably 
escape  the  attention  of  the  patient.  There  are  individuals  who 
have  a  dull  uncomfortable  sensation  in  the  jaw,  whenever  the 
formation  of  secondary  dentine  is  in  progress,  though  not  able 
to  locate  this  sensation  in  a  single  tooth.  Others  complain  of 
pain  in  the  dentine,  which  becomes  agonizing  whenever  the 
teeth  are  exposed  to  changes  of  temperature.  Still  others  are 
not  troubled  in  the  region  of  the  dentures  at  all,  but  suffer  from 
neuralgia  in  various  branches  of  the  trigeminus,  in  branches  of 
the  vagus,  or  even  of  the  cervical  plexus. 

The  irritations  here  spoken  of  may  be  caused  by  the  wearing 
off  of  the  crowns  through  advanced  age,  by  caries,  by  a  recession 
of  the  gums  at  the  necks  of  the  teeth,  by  erosion  and  mechanical  ab- 
rasion irrespective  of  age,  by  inflammatorj^  processes  in  the  peri- 
cementum, etc.  In  some  cases,  however,  no  such  cause  can  be 
discovered,  while,  nevertheless,  secondar}^  dentine  or  pulp-stones 
m.ay  be  found  to  have  developed  in  the  pulp-tissue,  even  in  the 
case  of  adolescents  from  sixteen  to  twenty  years  of  age.  In 
such  cases  we  account  for  this  fact  on  the  theory  that  frequent  ex- 
posure to  different  extremes  of  temperature,  as  in  eating  hot 
dishes  and  ices,  drinking  hot  and  ice-cold  liquids,  may  cause  the 
trouble. 

Irritation  may  affect  not  only  the  pulp-tissue,  but  the  dentine 
directly.  This  is  apparent  when  we  notice  the  consequences  of 
applying  caustic  or  metallic  filling-materials.  In  such  cases  the 
irritation,  in  the  portions  of  dentine  that  surround  the  fillings, 
leads  to  an  increased  afflux  of  serum,  saturated  with  lime-salts, 


IRRITATIOX    AND    XEW    FORMATIONS    OF    DENTAL    TISSUE.       291 

and,  consequently,  to  the  obliteration  of  a  number  of  dentinal 
canaliculi.  The  canaliculi  and  their  tenants,  the  fibers,  are  then 
transformed  into  basis-substance,  as  I  shall  show  in  a  further 
chapter. 

An  increase  of  bulk,  termed  "  hyperostosis  of  the  cementum," 
is  of  not  very  uncommon  occurrence  in  this  tissue.  Doubtless 
slight  but  incessant  irritation  is  here,  again,  the  cause  of  the  dis- 
turbance. As  to  the  source  of  the  irritation,  we  are  as  yet  in 
the  dark.  Wm.  H.  Atkinson  has  alleged  that  hyperostosis  of 
the  cementum  occurs  only  in  such  a  tooth  as  lacks  an  opponent. 
This  assertion,  however,  has  been  disproved  b}'  observation.  It 
is  possible  that  a  congenital  surplus  of  pericementum  in  the 
patient  is  productive  of  the  enlargement  of  the  cementum.  In 
this  case  the  movement  of  the  tooth  in  mastication  would  slightly 
exceed  the  normal  degree.  The  constant  irritation  of  the  peri- 
cementum under  such  conditions  might  cause  an  increase  in  the 
amount  of  the  cementum.  The  clinical  symptoms  of  hyper- 
ostosis are  just  as  obscure  as  those  of  the  growth  of  secondary 
dentine.  In  some  cases  the  patient  is  wholly  unconscious  of  the 
ailment ;  in  others  he  feels  uneasiness,  faint  discomfort,  or  even 
■dull  pain:  again,  in  others,  it  may  cause  reflex  irritation  in 
remote  parts, — neuralgia,  etc. 

In  this  chapter  I  have  endeavored  to  outline  a  process  sum- 
marized in  the  title  "Irritation  Causing  a  ISTew  Formation  of 
Dental  Tissue."  'No  strict  boundary-line  can  be  drawn  between 
this  process  and  that  which  results  in  the  formation  of  tumors. 
According  to  A.  Llicke,  irritation  and  inflammation  sooner  or 
later  come  to  a  standstill,  and  cease  to  be  instrumental  in  pro- 
ducing new  tissue;  whereas  tumors  grow  indefinitely,  never 
coming  to  rest  during^  life. 

In  the  absence  of  a  better  definition,  I  shall  adopt  that  of 
Liicke,  and  discuss  in  a  separate  chapter  the  congenital  or 
acquired  tumors  of  the  teeth. 


292      THE  AXATO.MY  AND  PATHOLOGY  OF  THE  TEETH. 

CHAPTER    XXVI. 

SECONDARY  DENTINE. 

In  the  preceding  chapter  I  have  stated  that  in  the  event  of 
irritation  on  the  surface  of  the  tooth,  the  pulp-tissue  reacts  and 
produces  secondary  dentine. 

Secondary  dentine  occurs  in  two  forms :  first,  secondary 
dentine  in  contact  with  primary  dentine  and  lining  the  pulp- 
cavity;  and  second,  dentine  in  the  middle  of  the  pulp-tissue. 
Whereas  the  etiology  of  secondary  dentine  of  the  former  variety 
is  plain,  alwaj's  being  the  result  of  an  irritation  on  the  surface 
of  the  tooth,  the  origin  of  the  so-called  pulp-stones  is  not  under- 
stood. The  latter  formations  are  often  met  with,  and  often  induce 
pulpitis. 

From  the  upper  jaw  of  a  lady  forty  years  of  age,  I  extracted 
the  cuspids,  one  of  which  I  split  to  obtain  the  pulp ;  the  other 
I  ground  thin  immediately  after  its  extraction,  for  the  purpose 
of  studying  enamel.  Only  one  longitudinal  section  could  be 
prepared.     The  results  were  as  follows  : 

The  crown  was  built  up  of  dentine  terminating  in  the  ordinary 
peak,  and  surrounded  by  a  well-developed  cap  of  enamel,  the 
outermost  point  of  which  was  lost,  evidently  in  the  grinding. 
(Fig.  163,  PD.)  A  marked  brown  discoloration  in  the  usual 
fan-like  arrangement  is  noticeable  in  the  enamel,  mainly  in  the 
immediate  neighborhood  of  the  dentine,  but  without  any  decay. 

The  dentine,  beginning  at  the  neck  and  extending  down  into 
the  root,  is  divided  into  two  layers,  one  internal,  occupying 
four-fiftbs  of  the  root,  and  one  external,  of  the  thickness  of  the 
cementum  of  normal  teeth.  These  two  layers  of  dentine  are 
sharply  marked  by  the  difference  in  the  carmin  stain,  the  inner 
portion  being  very  pale,  the  outer  deeply  colored.  The  boundary 
between  these  two  layers  is  everywhere  well  defined  by  a  scal- 
loped line,  the  concavities  of  which  look  outward.  In  some 
places  several  such  scalloped  marks  run  perfectly  parallel,  close 
to  one  another.  The  boundarj^  line,  however,  is  traversed  by  the 
dentinal  canaliculi  and  their  tenants  without  change  of  direction. 
The  outermost  portion  of  the  dentine  of  the  root  is  surrounded 
by  cementum,  not  thicker  than  is  seen  on  the  necks  of  teeth  of 
normal  development.  In  this  layer  faint  parallel  striations  are 
recognizable,  therefore  an  indistinct  lamellation.    The  cementum 


SECONDARY    DEXTIXE. 


293 


is  slightly  thicker  on  one  side  of  the  apex  of  the  root,  exhibiting 
there  a  scanty  number  of  cement-corpuscles,  \yhich  on  all  other 
portions  are  wanting. 

The  minute  structure  of  the  cementum  is  identical  with  that 
of  the  neck  of  a  normal  tooth, — built  up  of  delicate  wavy 
spindles  with  narrow  interstices.  These  spindles  are  missing 
only  on  that  side  of  the  root  where,  as  mentioned,  cement-cor- 
puscles are  present  and  the  basis-substance  exhibits  a  relatively 
coarse  granulation. 

Fig.  163. 


/ 


4> 


^^ 


^^ 


9m 


D 


Section'  of  the  Ceotvx  of  ax  Anomalous  Upper  Cuspid  Tooth. 

I),  D,  dentine ;  PD,  point  of  dentine  ;  E,  E,  enamel ;  SD.  secondary  dentine.    Magnified  50 
diameters. 


The  boundary  between  dentine  and  cementum  is  sharply 
defined.  The  former  bears  the  characteristics  of  dentine  in  the 
vicinit}^  of  the  neck,  as  the  canaliculi  stop  short  of  its  surface 
and  are  replaced  by  a  coarsely-granular  basis-substance.  Fig. 
164,  taken  from  the  lower  portion  of  the  root,  illustrates  the 
relations  just  described.     jSTearest  to  the  pulp-chamber  there  is 


294  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

a  zone  of  scanty  and  irregular  dentinal  canaliculi,  the  formation 
which  we  are  accustomed  to  call  "  secondary  dentine."  iSText 
to  this  is  a  broader  layer  of  dentine,  in  which  the  dentinal 
canaliculi  run  in  bundles  and  in  a  slightly  irregular  wavy  course. 
Then  we  see  a  broad  portion  of  fully-developed  dentine  (D),  the 
canaliculi  of  which  do  not  reach  the  cementum,  but,  beneath 


Root  of  ax  Axomalous  Cuspid  Tooth. 

D,  primary  dentine ;  LD,  secondary  dentine,  composed  of  two  zones ;  P,  pulp  ;  C,  cementum ; 
PC,  pericementum.    Magnified  300  diameters. 


the  latter,  are  replaced  by  a  coarseh'-granular  net-work.  The 
scalloped  boundary  between  LD  and  D  is  plainlj^  marked.  On 
the  outer  surface  appears  the  relatively  narrow  layer  of  ce- 
mentum (C)  with  its  lamellated  structure,  and,  attached  to  this, 
remnants  of  the  pericementum  {PC)  are  visible.  Higher  mag- 
nifying powers  of  the  microscope  give  an  insight  into  the  minute 


SECONDARY    DEXTIXE. 


295 


structure  of  the  dentine  and  cementum  (see  Fig.  165),  taken  from 
the  place  just  described.  In  the  layer  of  dentine  the  termina- 
tions of  the  dentinal  fibers  are  seen  bifurcated  and  leading  to- 
ward the  light  reticulum,  in  which  we  assume  the  presence  of 
living  matter.  The  lamellated  cementum  is  provided  with  a 
number  of  curved  spindles,  evidently  of  protoplasmic  nature^ 
which  in  their  general  direction  correspond  to  the  course  of  the 
dentinal  fibers,  while  the  basis-substance  between  the  spindles 
appears  finely  granular.  On  that  portion  of  the  cementum  of 
the  root  which  is  provided  with  cement-corpuscles  a  distinct 


Fig.  165. 


f: 


D- 


RooT  OF  AS  Anomalous  Cuspid  Tooth. 
D,  dentine ;  C\  cementum ;  P,  pericementum.    Magnified  1000  diameters. 


boundary  between   dentine  and  cementum    is  wanting. 


The 


pericementum  everywhere  is  attached  to  the  cementum  by  rows 
of  spindle-shaped  bodies  in  the  same  manner  in  which  we  see  it 
on  the  necks  of  normal  teeth. 

In  this  tooth,  therefore,  the  cement-layer  is  replaced  by  a 
regularly-developed  layer  of  dentine,  the  former  being  very  thin, 
and,  with  the  exception  of  a  limited  portion,  devoid  of  cement- 
corpuscles.  Evidently  the  tooth  originally  had  a  very  large 
pulp-charnber,  which,  with  advancing  age,  was  reduced  by  the 
formation  of  dentine,  first  regularly  and  afterwards  irregularly 


296 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


provided  with  dentinal  canaliculi.     The  central  portion  of  the 
dentine  is  occupied  bj  "  secondary  dentine." 

In  the  crown,  a  conical  portion,  the  blunt  lower  edge  of  which 
binds  the  pulp-cavity  (see  Fig.  163,  SD),  exhibits  a  structure 
which  doubtless  has  all  the  essential  properties  of  dentine, 
though  in  a  considerably  more  irregular  arrangement  than 
ordinary  dentine.  The  regular  dentine  terminates  almost 
abruptly  all  around  the  cone  of  the  irregular  dentine.     On  the 


ripT^^.;:;ni!'::a;liisi]m 


Fig.  166. 

r!fi»!iiiip;>:i;:i!!jpii?r!;?Fpiiiii';'i!iii|!iij; 


SB 


vvL 


V  ;■ 


I  ^ 


i 


CtJSP  OF  AX  ANOiiALOUS  Cuspid  Tooth. 

D,  dentine  :  SB,  secondary  dentine  ;  pi.  pear-shaped  protoplasmic  bodies  on  the  boundary 
between  primary  and  secondary  dentine,  sending  large  offshoots,  0,  downward ;  P-,  protoplasmic 
body  without  offshoots.    Magnified  500  diameters. 


apex  of  the  latter  are  visible  large,  irregularlj'-shaped  branching 
spaces,  which  invariably  contain  partly-nucleated  protoplasmic 
formations.  (See  Fig.  166.)  The  spaces  and  their  respective  ten- 
ants, the  protoplasmic  bodies,  are  mainly  pear-shaped,  with  their 
bases  directed  toward  the  regular  dentine,  and  their  elongations 
passing  into  the  irregular  dentine.  From  the  broad  bases  arise 
numerous  conical  offshoots,  by  means  of  which  a  direct  com- 
munication is  established  with  the  dentinal  fibers  of  the  reg-ular 


SECONDARY    DENTINE.  297 

dentine,  while  other  oftshoots  inosculate  with  analogous  forma- 
tions on  the  apex,  thus  producing  a  coarse  net-work.  From  the 
pointed  lower  ends  of  the  pear-shaped  spaces  originate  wavy 
canaliculi,  which  freely  anastomose  with  one  another,  and  traverse 
the  whole  mass  of  the  central  portion  of  the  crown  in  a  prevail- 
ing radiate  arrangement.  Their  number  is  more  scanty  than  in 
the  regular  dentine,  so  much  so  that  relatively  large  territories 
of  the  basis-substance  are  altogether  devoid  of  canaliculi.  The 
latter,  like  the  canaliculi  of  normal  dentine,  hold  delicate  beaded, 
fibers  of  living  matter,  with  the  difference  that,  on  the  average, 
the  fibers  of  normal  dentine  are  finer  than  those  of  the  second- 
ary formation.  Some  of  these  fibers  are  provided  with  lateral 
conical  offshoots  directed  toward  the  basis-substance,  which  itself 
shows  a  delicate  reticular  structure  essentialh-  of  the  same  char- 
acter as  I  have  seen  in  regular  dentine. 

The  middle  portion  of  the  pulp-cavity  is  bounded  by  a  narrow 
zone  of  dentine,  which, is  possessed  of  canaliculi  in  a  smaller 
number  than  the  main  mass  of  dentine.  This  zone,  besides,  is 
characterized  by  a  deep  car m in  stain,  while  the  regular  dentine 
remained  almost  unstained.  The  stained  portion  is  inserted 
upon  the  regular  dentine  by  means  of  numerous  shallow  excava- 
tions, and  its  surface  is  irregularly  jagged  toward  the  pulp-cavity. 
In  the  apex  of  the  root,  the  irregular  formation  of  dentine 
again  is  much  thicker  than  in  the  middle  portion,  and  provided 
with  numerous  roundish  spaces,  all  of  which  contain  protoplasm, 
and  communicate  with  the  irregular,  wavy  canaliculi  of  the 
boundary  layer  of  the  pulp-cavity. 

From  the  facts  recorded  in  dental  literature,  it  is  evident 
that  there  are  several  causesuniversally  agreed  upon  as  to  forma- 
tions of  secondary  dentine.  These  causes  are  mainly :  first, 
advanced  age ;  second,  caries  of  the  primary  dentine ;  and  third, 
injuries  on  the  external  surface  of  the  tooth. 

Carl  Heitzmann,  in  1872,*  first  drew  attention  to  the  fact  that 
in  old  dogs  and  cats  a  number  of  Haversian  canals  in  the  com- 
pact bone  become  obliterated.  This  investigator  observed  that 
the  capillary  blood-vessel,  which  represents  the  last  remnant 
of  the  medullary  tissue  within  the  Haversian  canals,  is  finally 
transformed  into  a  solid  protoplasmic  mass,  which  immediately 
assumes  the  character  of  the  bony  basis-substance.     The  bone- 

*  "  Uber  Eiick-  und  Neub^ldung  von  Blutgefassen  in  Knorpel  und  Knochen," 
JVlene/-  Medicinische  Jahrbucher. 


298  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

corpuscles,  which  under  these  circumstauces  are  visible  in  the 
center  of  a  Haversian  system,  are,  as  a  rule,  larger  than  those 
scattered  within  the  lamellae  of  an  earlier  formation. 

If  we  consider  the  pulp-cavit}'  as  a  medullary  space  containing^ 
blood-vessels,  nerves,  and  medullary  elements,  around  which  are 
arranged  the  layers  of  dentine,  enamel,  and  cementum,  we  find 
a  coincidence  of  the  formation  of  bone  on  the  one  hand,  and  of 
secondary  dentine  on  the  other,  in  advancing  age.  In  both 
instances  the  medullary  elements  are  transformed  into  basis- 
substance;  the  nerves,  probably,  after  having  been  reduced  to 
medullary  elements,  also  assisting  in  the  formation  of  secondary 
dentine;  and,  lastly,  the  blood-vessels  are  solidified.  On  an 
average,  the  older  the  person  the  smaller  is  the  pulp-cavity,  until 
at  last  hardly  any  trace  of  the  pulp-tissue  is  left,  and  the  tooth 
is  an  almost  completely  solid  mass. 

Opposed  to  carious  destruction  of  the  crown  I  have  repeatedly 
met  with  formations  of  secondary  dentine,  as  described  by  Salter 
and  Wedl.  This  occurred,  however,  only  in  those  forms  of 
caries  which  have  been  described  by  Frank  Abbott  as  chronic. 
I  have  specimens  which  illustrate  that  such  secondary  dentine 
formations,  when  the  carious  process  has  led  to  the  exposure  of 
the  pulp  and  produced  pulpitis,  are  again  partially  destroyed  by 
the  inflammatory  process. 

As  to  the  irritation  from  without,  first  stated  by  Salter  to  be- 
the  cause  of  the  formation  of  secondary  dentine,  I  would  add 
chronic  pericementitis,  which,  when  limited  to  one  root  or  to  a 
portion  of  the  root,  leads  to  the  formation  of  secondary  dentine 
in  the  pulp-canal  of  the  afiFected  root.  There. are  cases,  how- 
ever, in  which  neither  age  nor  an  external  injury  accounts  for 
the  formation  of  secondary  dentine;  and  one  instance  is  that  of 
the  tooth  above  described.  Here,  perhaps,  the  absence  of  the 
fully-developed  layer  of  cementum  was  the  reason  for  such  an 
extensive  premature  formation  of  secondary  dentine. 

The  coarser  anatomical  relations  of  secondary  dentine  in 
general  are  accurately  described  by  C.  Wedl,  with  whom  I  fully 
agree.  In  analyzing  the  manifold  formations  of  this  kind,  I 
would  divide  them  as  follows  : 

First.     Secondary'  dentine  resembling  primary  dentine. 

Second.     Secondary  dentine  with  a  laminated  structure. 

Third.  Secondary  dentine  in  form  analogous  to  Haversian 
systems.     This  latter  variety  has  been  termed  "  osteo-dentine."' 


SECONDARY    DENTINE.  299> 

Secondary  dentine,  with  the  essential  structure  of  primary 
dentine,  is  evidently  of  the  most  frequent  occurrence.  It  never 
has  the  regular  arrangement  of  the  dentinal  canaliculi  as  seen 
in  primary  dentine,  but  is  marked  by  a  lighter  color,  owing  to^ 
the  large  amount  of  basis-substance  and  the  relatively  small 
number  of  canaliculi,  which  at  the  same  time  deviate  more  or 
less  from  the  direction  of  the  primary  canaliculi.  In  cross- 
sections  of  such  secondary  dentine, — especially  in  specimens 
stained  with  chloride  of  gold, — we  recognize  in  each  canaliculus 
a  central  fiber  (Fig.  167),  from  which  delicate  conical  offshoots 
emanate  toward  the  peripher}-  of  the  canaliculus.  The  canaliculi, 
which  as  a  rule  are  the  wider  the  nearer  to  the  pulp-cavity,  are 
pierced  on  their  periphery  by  light  interruptions,  leading  into 
a  delicate  light  reticulum  throughout  the  whole  basis-substance. 

Fig.  167. 


—LZ' 


Dextixe  of  ax  Aged  Peesox.    Ceoss-Skctiox. 
PB,  primary  dentine  ;  LD.  secondary  dentine.    Magnified  1000  diameters. 

In  the  reticulum,  the  presence  of  living  matter  is  not  directly 
demonstrable,  but  it  must  be  assumed  mainly  from  the  phe- 
nomena of  inllammation, — viz,  caries  and  pulpitis.  The  second- 
ary dentine  sometimes  remains  in  an  embryonal  condition,  ex- 
hibiting roundish  fields  of  basis-substance,  such  as  are  visible  in 
the  dentine  of  a  nine-months'  foetus.  The  medullary  elements 
being  transformed  into  basis-substance,  represent  irregular  glob- 
ular bodies,  between  which  the  living  matter  produces  the 
formations  known  as  Tomes's  dentinal  fibers. 

This  much  is  certain,  that  the  dentinal  fibers  of  secondary 
dentine  are  also  beaded,  and  send  lateral  offshoots  toward  the 
basis-substance,  thus  indicating  the  presence  of  living  matter  in, 
the  latter.     (Fig.  168.) 


300      THE  ANATOMY  AND  PATHOLOaY  OF  THE  TEETH. 

Formations  known  as  "  interglobular  spaces"  are  not  infre- 
quently met  with  in  normal  dentine.  Thej^  are  also  quite  com- 
mon in  secondary  dentine,  especially  on  tlie  boundary  between 
primary  and  secondary  dentine.  The  tooth  first  described  (Figs. 
163  and  166)  furnishes  beautiful  samples  of  such  formations. 
Most  of  these  are  protoplasmic  in  nature ;  nay,  some  exhibit 
distinct  nuclei.  The  offshoots  are  evidently  fibers  of  living 
matter.  Some  of  these,  toward  the  primary  dentine,  are  in 
direct  communication  with  its  fibers;  others  run  in  difierent 
directions  toward  neighboring  kindred  formations,  with  which 


Fig.  168. 


If^w  'f 


—IB 


;-  ] 

Secondary  Dextixe,  with  Globular  Formations  of  the  Basis-Substance. 

PB,  primary  dentine  ;  SD,  secondary  dentine,  with  irregularly-scattered  eanaliculi ;  IB, 
globular  bodies  of  secondary  dentine,  between  which  the  dentinal  eanaliculi  run,  all  in  con- 
nection with  those  of  the  primary  dentine.    Magnified  500  diameters. 

they  inosculate;  others  again,  after  repeated  bifurcation,  lose 
themselves  in  the  basis-substance.  Exceptionally  there  occur 
also  protoplasmic  bodies  without  any  coarser  offshoots.  (Fig. 
166.) 

Higher  amplification  of  these  formations  plainly  demonstrates 
their  minute  structures.  (Fig.  169.)  We  see  protoplasmic 
bodies  imbedded  in  lacunse  of  the  basis-substance,  essentially 
identical  with  the  so-called  "  interglobular  spaces,"  the  tenants 
of  which  never  could  have  been  made  out  in  sections  obtained 
from  dry  teeth.    The  protoplasmic  bodies  send  in  different  direc- 


SECONDARY    DENTINE.  301 

tions  into  the  basis-substance,  larger  beaded  fibers,  which  are 
partly  in  communication  with  fibers  arising  from  neighboring 
bodies.  Some  of  the  canaliculi  I  found  empty,  from  which  the 
fibers  (evidently  in  the  process  of  grinding)  have  been  torn  out. 
The  protoplasmic  bodies  on  their  peripher}^  send  conical  thorns 
through  the  light  spaces  between  the  protoplasm  and  the  wall  of 
the  lacuna  or  interglobular  space.  The  pointed  ends  of  these 
thorns  are  directed  toward  the  light  reticulum,  which  pierces 
the  basis-substance  everywhere. 

The  second  variety  of  secondary  dentine  consists  of  the  for- 
mation of  a  lamellated  basis-substance,  which  is  traversed  by 
irregular  dentinal  canaliculi.     I  have  observed  in  my  specimens 

Fig.  169. 


r'S?j- 


SECu^uAKi    i>j-,>ii>h  1  KiiM  Clsfid. 

P,  protoplasmic  bodies  with  the  reticular  structure  and  offshoots ;  S,  basis-substance  with  the 
light,  net-like  structure.    Magnified  1000  diameters. 

that  the  lamellated  structure  begins  close  to  the  termination  of 
the  primary  dentine  in  an  almost  continuous  course.  The  la- 
mellae themselves  never  are  very  regular,  and  produce  broader 
and  narrower  layers,  which,  as  a  rule,  are  not  strictly  parallel  to 
one  another.  In  the  interstices  between  the  lamellae,  here  and 
there,  I  have  met  with  flat  layers  of  protoplasm.  The  canal- 
iculi piercing  the  lamellated  dentine  are  generally  very  narrow, 
and  run  either  perpendicular  or  oblique  to  the  lamellae,  with 
manifold  ramifications.  They  invariably  contain  delicate  beaded 
fibers  of  living  matter,  which  send  lateral  conical  ofishoots  to- 
ward the  basis-substance,  in  a  much  more  irregular  distribution 
than  we  see  in  primary  dentine. 


^302  THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

On  the  boundaiy  between  primary  and  secondary  dentine  we 
very  often  sncceed  in  tracing  a  direct  continuity  of  the  canaliculi 
of  the  former  with  those  of  the  latter. 

The  figure  (Fig.  170)  which  illustrates  the  lamellated  variety 
of  secondary  dentine  exhibits  a  peculiar  feature  of  dentinal 
canaliculi  in  the  primary  dentine,  near  its  connection  with  the 
lamellated.  formation, — viz,  bifurcations  of  the  canaliculi  of  the 
primary  dentine,  which  otherwise  do  not  occur  except  on  their 
terminations  near  the  enamel  and  the  cementum.  The  second- 
ary dentine  shows  bay-like  excavations  bordering  the  pulp-cavity, 
-evidently  due  to  an  inflammatory  process  of  the  pulp-tissue,  which 


EiG.  170. 


1 


FD 


SJ) 


Lamellated  Variety  of  Secondary  Dextixe. 

PD,  primary  dentine  ;  SD,  secondary  dentine ;  P,  margin  toward  pulp-cavity,  with  bay-like 
excavations,  due  to  pulpitis.  Tiie  lamellae  of  the  secondary  dentine  are  irregular  and  pierced 
■by  dentinal  fibers,  some  of  which  are  in  direct  connection  with  those  of  the  primary  dentine. 
Magnified  500  diameters. 

has  led  to  the  dissolution  of  the  lime-salts.  In  the  specimen 
from  which  I  have  taken  the  drawing  the  layer  of  the  lamellated 
dentine  is  very  broad  toward  the  crown  and  apex  of  the  root ; 
while  the  middle  portion  of  the  pulp-cavity,  though  considerably 
narrowed,  has  a  relatively  small  amount  of  secondary  dentine 
on  its  limits. 

The  third,  and  evidently  rarest,  form  of  secondary  dentine  is 
that  known  by  the  term  "  osteo-dentine."  Formations  of  this 
kind  are  either  pedunculated, — i.e.,  connected  with  the  primary 
dentine  by  a  stem, — or  they  partly  fill  the  pulp-cavity  in  the 


SECONDARY    DENTINE.  303 

shape  of  a  uniform  layer.  There  is  a  striking  resemblance 
between  osteo-dentine  and  Haversian  systems  of  bone-tissue. 
The  systems  greatly  vary  in  size  and  shape,  and  are  separated 
from  one  another  by  a  tissue  kindred  to  primary  dentine,  but 
■devoid  of  dentinal  canalieuli.  Each  system  has  in  its  center  a 
medullary  canal,  containing  a  certain  amount  of  protoplasmic 
bodies  known  as  medullary  elements;  nay,  in  some  of  the  sys- 
tems I  have  met  with  a  central  capillary  blood-vessel,  which  has 
■evidently  been. in  direct  union  with  capillaries  of  the  pulp-tissue. 
Around  the  medullary  canal  a  system  of  lamellae  is  arranged, 

Fig.  171. 


•/ 


j^i-' 


J)  -— - 


OSTEO-DEXTIXE,   THE  ThIED   VaEIETY  OF  SeCOXDART    DesTIXE. 

D.  primary  dentine  ;  SD,  secondary  dentine ;  SL,  system  of  lamellse,  resembling  those  of 
Haversian  systems  of  bone  ;  MC,  medullary  canal  filled  with  protoplasm  :  BC,  small  protoplas- 
mic elements,  identical  with  bone-corpuscles :  EP,  erosions  of  osteo-dentine,  due  to  pulpitis. 
JMagnified  600  diameters. 

sometimes  pretty  regularly;  and  the  lamella  are  traversed  by 
delicate  radiating  canalieuli,  closely  resembling  those  of  bone- 
tissue.  Only  exceptionally  have  I  seen  within  the  lamellae  proto- 
plasmic formations  analogous  to  bone-corpuscles.  The  jagged 
outlines  of  the  lacunse,  in  which  the  protoplasmic  bodies  lodge, 
are  identical  with  those  found  in  bone;  and  higher  magnifying 
powers  of  the  microscope,  in  fact,  reveal  an  open  communication 
of  the  lacuna  with  the  adjacent  canalieuli. 


304  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

In  the  specimen  from  which  I  have  selected  a  spot  for  illustra- 
tion (Fig.  171),  the  lamellated  systems  were  developed  in  a  most 
marked  manner ;  and  the  blood-vessels  in  the  center  of  these 
systems  were  so  regular  that  they  suggested  the  query  whether 
or  not  we  had  here  to  deal  with  vaso-dentiue,  so  common  in  the 
teeth  of  fish.  These  formations  occurred  in  the  apex  of  the 
root, — some  of  them  in  the  midst  of  regular  dentine, — while 
the  lowest  systems,  without  any  distinct  boundary,  were  con- 
nected with  the  cementum,  which  latter  here  and  there  also  ex- 
hibited medullary  canals. 

Fig.  172. 


Secondary  Dentine  of  Permanent  Molar,  Stained  with  Chloride  of.Gold,  Decal- 
cified ■WITH  Acetic  Acid. 

F,  F,  dentinal  fibers ;  B,  B,  basis-substance.    Magnified  1200  diameters. 

A  contribution  to  the  minute  anatomy  of  secondary  dentine 
is  published  by  John  I.  Hart.*  His  results  were  obtained  in  a 
treatment  of  protracted  staining  with  a  solution  of  chloride  of 
gold: 

"  In  several  of  my  specimens  of  permanent  teeth,  I  have[met 
with  secondary  dentine  toward  the  pulp-chamber.     I  have  seen 

*  "Minute  Structure  of  Dentine."     Detital  Cosmos,  1891. 


SECONDARY    DEXTIXE.  305 

its  two  main  varieties :  the  one  characterized  by  the  presence  of 
irreo-ular  and  wavy  dentinal  canaliculi,  distributed  in  the  basis- 
substance  in  the  form  of  bundles  or  sheaves,  and  the  other 
marked  by  the  presence  of  bone-corpuscles,  the  so-called  osteo- 
dentine.  I  must  confine  my  remarks  to  the  former  variety,  as 
the  latter  was  seen  accidentally,  in  dead  teeth  only.  (See 
Fig.  172.) 

"  The  dentinal  fibers  are  rather  large,  and  supplied  with  nu- 
merous vacuoles  in  their  substance.  jSTumerous  coarser  lateral 
offshoots  arise  from  these  fibers,  apparently  more  numerous 
than  in  primary  dentine.  Besides,  there  were  seen  coarse 
conical  offshoots  springing  from  the  periphery  of  the  dentinal 
fibers  and  running  into  a  reticulum,  which,  in  some  places  at 
least,  was  coarser  than  that  of  the  primary  dentine.  This  re- 
ticulum also  appeared  more  irregular  in  the  secondary  than  in 
the  primary  dentine." 

11.  Secondary  Dentine  in  the  Middle  of  the  Pulp-Tissue.— 
What  previous  observers  have  termed  "  pulp-stones"  or  "  den- 
ticles" I  propose  to  designate  as  "  dentinification,"  "  eburnifica- 
tion,"  and  "  ossification"  of  the  pulp-tissue. 

It  was  necessary  to  invent  such  terms  for  the  designation  of 
a  process  which,  although  known  for  many  years,  has  never 
been  fully  understood.  I  refer  to  the  new  formation  of  dentine 
in  the  middle  of  the  pulp-tissue,  independent  of  the  dentine 
composing  the  walls  of  the  pulp-chamber.  It  is  the  formation 
of  the  so-called  "  pulp-stones"  which  by  some  observers  are  an- 
nounced as  the  result  of  a  process  of  calcification,  but  by  John 
Tomes,  Ulrich,  Hohl,  Bruck,  Baume,  and  "Witzel  have  been 
described  as  a  variety  of  secondary  dentine.  So-called  pulp- 
stones,  as  is  well  known,  may  be  found  either  connected  with 
the  dentine  proper  by  means  of  a  peduncule,  or  loosely  im- 
bedded in  the  connective  tissue  of  the  pulp.  Most  of  these 
formations  are  composed  of  dentinal  tissue  in  the  form  termed 
secondary  dentine.  Of  rarer  occurrence  are  those  constructed 
exclusively  of  a  lamellated  bone-tissue.  Somewhat  rarer  still 
are  combinations  of  both  dentine  and  bone-tissue.  The  rarest 
are  new  formations  of  dentine  strictly  identical  with  primary 
dentine. 

1.  So-called  "  pulp-stones"  of  the  character  of  secondary  den- 
tine. The  most  marked  characteristic  of  these  specimens  is  the 
presence  of  dentinal  canaliculi  irregularly  scattered  throughout 

21 


306  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

the  calcified  basis-substance.  Sometimes  the  canaliculi  assume 
a  tolerably  Avell-marked  radiation ;  in  other  instances,  even 
large  masses  of  calcified  basis-substance  are  destitute  of  canali- 
culi. These,  in  scanty  bundles,  are  found  toward  the  periphery 
of  the  pulp-stone.  All  the  three  varieties  of  secondarj^  dentine 
are  found  in  these  formations.  Portions  of  the  basis-substance, 
especially  toward  the  periphery,  may  exhibit  delicate  concentric 
laminations.  In  the  midst  of  an  apparently  homogeneous  basis- 
substance,  small  laminated  territories  may  occur,  containing  a 
central  corpuscle  with  branching  offshoots,  somewhat  resembling 


Eburnification.— Section  of  a  Pulp-Stone  of  a  Lower  Molar. 

X,  lamellated  secondary  deutine,  traversed  by  radiating  dentinal  canaliculi;  C,  C,  globular 
masses,  exhibiting  a  concentric  striation.    Magnified  300  diameters. 

a  bone-corpuscle.  In  sections  of  one  pulp-stone,  I  have  found 
numerous  concentrically-laminated  territories,  more  or  less  dis- 
tinct, and  either  one  or  two  protoplasmic  formations  in  their 
centers.  The  tissue  between  the  territories  was  partly  granular 
and  partly  composed  of  secondary  dentine,  with  irregular  canali- 
culi. Here  and  there  medullary  spaces  were  seen  traversing 
the  tissue,  from  which  evidently  the  new  formation  of  the  terri- 
tories had  started.  This  variety  is  the  regular  osteo-dentine. 
2.  So-called  "  pulp-stones"  composed  of  regularly-developed 


SECOXDARY    DENTIXE.  307 

laminated  bone.  I  have,  as  mentioned  before,  examined  pulps 
composed  almost  exclusively  of  a  dense  fibrous  connective  tissue, 
the  bundles  of  which  were  so  interlaced  in  all  directions  as  to 
establish  a  regular  cicatricial  connective  tissue.  Scanty  nerve- 
bundles  and  blood-vessels  traverse  the  dense  connective  tissue, 
which  in  some  places  appears  to  be  more  or  less  crowded  with 
medullary  or  inflammatory  corpuscles.  In  such  fibrous  pulps  I 
have  observed  smaller  or  larger  masses  of  fidly-developed  bone- 
tissue,  composed  of  more  or  less  regular  lamellae,  or  of  calcified 
fibrous  lamellae.     In  these  a  large  number  of  irregular  branch- 

FiG.   174. 


V 


I  f)^k\^  '^- 


^^^ 


OssiFiCATiox.— Section  of  Pulp  of  Upper  Latekal. 

L,  longitudinal,  T,  transverse  bundles  of  cicatricial  fibrous  connective  tissue ;  B,  spicula  of 
lamelldted  bone.    Magnified  5U0  diameters. 

ing  bone-corpuscles  are  seen,  arranged  in  rows  or  chains,  where 
the  basis-substance  shows  a  more  fibrous  character.  Sometimes 
the  bone-tissue  appears  in  lamellated  islands,  sharply  marked 
from  the  surrounding  fibrous  tissue.  K"o  formations  of  second- 
ary dentine  were  combined  in  these  cases  with  the  bone-tissue. 
3.  So-called  '-pulp-stones"  composed  of  a  mixture  of  regular 
bone  and  dentinal  tissue.  In  rare  instances  I  have  met  with 
pulp-stones  partly  composed  of  secondary  dentine  and  lamel- 
lated bone  in  such  a  wav  that  irregularlv-bounded  masses  of 


308  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

bone  contained  a  few  large  bone-corpuscles,  alternately  sur- 
rounded by  a  basis-substance,  which  contained  only  irregular, 
wavy,  dentinal  canaliculi. 

4.  So-called  "  pulp-stones"  composed  of  dentine  with  the  fea- 
tures of  primary  dentine.  I  have  examined  a  large  number  of 
pulp-stones;  one  of  them,  a  mass  about  the  size  of  a  pea,  was 
built  up  of  dentine.  The  canaliculi  of  this  dentine  are  per- 
fectly parallel,  and  between  these  a  finely-reticular  basis-sub- 
stance was  found,  arranged  in  the  same  way  as  in  primary  dcn- 

FiG.  175. 


'  fM 


"PD 


Dextixification.— Section  of  Pulp-Stoxe  of  Upper  Molar. 

PB,  primary  dentine;  SB,  secondary  dentine;    0,  irregularly-lamellated  bone-tissue;   G^ 
granular  layer  toward  the  pulp-tissue.    Magnified  500  diameters. 

tine  of  temporary  teeth  of  children,  which  teeth  are  generally 
poorly  supplied  with  lime-salts.  In  this  specimen,  too,  the  den- 
tinal canaliculi  are  wide;  the  basis-substance  between  them,  on 
the  contrary,  is  narrow.  The  dentinal  fibers  are  relatively 
bulky  beaded  formations,  with  numerous  large  conical  spokes 
penetrating  the  peripheral  space  of  the  canaliculi.  This  regu- 
lar dentine  toward  the  periphery  of  the  pulp-stone  is  bounded 
by  a  slightly-fluted  contour,  a  narrow  zone  of  which  exhibits  the 


MECHANICAL    ABRASION.  309 

structure  of  canaliculated  secondary  dentine.  This  zone  blends 
with  a  still  narrower  one,  which  is  composed  of  an  indistinctly 
lamellated  bone-tissue,  wherein  bone-corpuscles,  large  in  size 
but  few  in  number,  are  imbedded.  This  layer  is  followed  by 
the  bounding  layer  of  the  specimen.  The  latter,  which  has  a 
granular  appearance,  contains  a  few  angular  or  spindle-shaped 
protoplasmic  bodies  and  a  few  dentinal  canaliculi. 


CHAPTEE    XXA^IL 

MECHANICAL  ABRASION. 

This  term  is  applied  to  the  process  in  which  the  teeth  suffer 
loss  by  attrition.  Mechanical  abrasion  is  a  result  of  imperfect 
articulation,  advanced  age,  or  of  an  imperfect  calcification  of  the 
enamel  and  the  dentine  of  the  teeth.  Under  normal  conditions 
the  cuspid,  the  bicuspid,  and  the  molar  cusps  fit  accurately 
into  the  depressions  of  the  teeth  in  the  opposite  jaw.  Even  upon 
the  incisor  teeth,  when  they  are  first  shed,  especially  on  the 
lower  ones,  we  notice  three  protuberances,  which,  through  wear, 
soon  disappear.  In  a  normally  articulating  set  of  teeth,  the 
cusps  of  the  bicuspids  and  molars  are  not  easily  worn  oft",  and 
the  incisors  and  cuspids  are  almost  entirely  relieved  of  wear, 
so  that  we  sometimes  meet  with  persons  fifty  years  of  age  who 
still  have  the  enamel  upon  the  cusps  of  their  teeth  preserved. 
As  a  rule,  however,  most  people  lose  some  of  their  molar  teeth 
before  their  thirtieth  year.  The  consequence  of  the  loss  of 
teeth  out  of  the  dental  arch  is  a  contraction  of  the  jaw,  and  if 
one  or  two  of  the  back  teeth  be  lost  from  the  same  side  of  one 
jaw,  the  result  will  be  an  imperfect  articulation,  unless  the  corre- 
sponding teeth  be  removed  from  the  jaw  opjoosite.  In  correct- 
ing protrusions  of  either  the  upper  or  the  lower  jaw,  it  sometimes 
happens  that  we  need  only  remove  the  corresponding  two  upper 
or  lower  first  permanent  molars. 

Frequently  we  see  that  where  a  few  years  ago  a  single  molar 
or  bicuspid  has  been  removed  from  either  the  upper  or  the  lower 
jaw,  the  subsequent  contraction  of  the  dental  arch  has  almost 
closed  up  the  gap.  In  the  displacement  of  the  remaining  back 
teeth,  the  points  of  the  cusps  come  in  contact  with  one  another, 


310  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

and  are  conseqiientlj  worn  off;  and  correspondingly,  as  the  two 
jaws  come  closer  together,  the  upper  front  teeth  are  worn  out 
on  their  lingual  surfaces.  After  the  enamel  of  a  molar  tooth 
has  been  worn  off,  the  dentine  wears  away  much  faster  than 
the  enamel  does.  Where  formerly  the  cusps  of  the  tooth  were 
situated,  we  now  see  depressions  in  the  dentine.  Later  on, 
again,  when  the  grinding-surface  of  the  tooth  has  lost  all  the 
enamel  of  its  fissures,  the  dentine  is  eroded  much  faster  than  the 
enamel  that  still  surrounds  the  crown.  In  such  cases  a  molar 
tooth  presents  a  cup,  the  dentine  in  the  center  sometimes  being 
worn  away  up  to  the  pulp-chamber,  while  the  surrounding  enamel 
of  the  tooth  forms  a  more  or  less  sharp,  ragged,  high  ridge.  In 
a  few  instances  only  the  enamel  of  the  labial  surfaces  of  the 
upper  incisor  teeth  is  left,  while  the  enamel  of  the  labial  surfaces 
of  the  corresponding  lower  incisors  is  lost. 

Occasionally  we  see  persons  who  have  lost  one  or  two  teeth  of 
the  upper  jaw  before  the  tenth  or  twelfth  year  of  age,  in  conse- 
quence of  which  the  upper  jaw  is  retracted  while  the  lower  one 
continues  to  develop.  In  such  cases  a  protrusion  of  the  lower 
jaw  gradually  follows,  and  the  teeth  then  articulate  only  at  their 
cutting-edges  and  the  points  of  their  cusps.  In  such  an 
abnormal  articulation,  the  person  acquires  a  habit  of  using  the 
lower  jaw  in  a  rotary  movement,  by  means  of  the  pterygoid 
muscles.  The  antagonizing  teeth  then  wear  upon  one  another, 
so  much  so  that  in  a  few  years  the  cusps  disappear,  and  the 
incisors  sometimes  become  worn  down  to  the  gum,  presenting 
a  more  or  less  flat,  smooth  grinding-surface,  similar  in  shape  to 
that  of  a  worn-off  bicuspid.  Smokers  who  use  clay  pipes,  hold- 
ing them  mostly  between  the  same  teeth,  often  exhibit  on  these 
teeth  abraded  notches  of  a  shape  fitted  to  the  pipe-stem. 

In  mechanical  abrasion,  much  depends  upon  the  hardness  of 
the  teeth,  as  well  as  the  kind  of  food  used  by  the  individual. 
R.  Baume  states  that  some  savage  tribes  add  sand  to  their  food, 
which  wears  their  teeth  away  in  early  life.  Other  persons,  and 
especially  highly  civilized  people,  prepare  their  food  in  such  a 
manner  that  the  teeth  are  called  upon  to  do  but  little  mastica- 
tion, in  which  case  the  enamel  upon  the  cusps  remains  intact  to 
the  fiftieth  year  of  age  or  even  longer.  Wherever  the  tooth 
loses  its  enamel,  it  becomes  sensitive  to  the  action  of  weak  acids, 
to  thermal  changes,  and,  more  or  less,  to  mastication.  The 
degree  of  the  sensitiveness  of  the  abraded  surfaces,  however, 


MECHANICAL    ABRASIOX.  311 

mainly  depends  upon  the  chemical  composition  of  the  fluids  of 
the  mouth.  Saliva,  when  of  a  distinct  acid  reaction,  always 
causes  considerable  sensitiveness  of  these  surfaces. 

As  to  the  pathology  of  mechanical  abrasion,  little  can  be  said. 
Both  ground  specimens  and  those  obtained  after  decalcification 
in  chromic-acid  solution  show  abrupt  terminations  of  the  enamel- 
prisms  as  well  as  of  the  dentinal  canaliculi,  without  a  trace  of 
reaction.  Occasionally  along  the  border  of  the  abraded  surface 
a  narrow  zone  of  decalcification,  parallel  to  the  contour  of  the 
abrasion,  is  seen.  In  specimens  treated  with  a  solution  of  am- 
moniacal  carmin,  the  decalcified  zone  assumes  a  saturated  pink 
color.  I  have  tried  to  stain  a  number  of  ground  specimens  of 
teeth  affected  by  mechanical  abrasion,  with  solution  of  chloride 
of  gold,  followed  by  decalcification  in  a  six  per  cent,  solution  of 
glacial  acetic  acid.  All  these  experiments  failed,  because  before 
the  calcified  dentine  had  more  than  begun  to  exhibit  the  details 
of  its  structure,  the  decalcified  zone  was  already  of  a  deep  violet, 
nearly  black  color,  that  precluded  the  study  with  even  medium 
powers  of  the  microscope.  The  presence  of  a  decalcified  zone 
close  beneath  the  abraded  surfiice  suificientl}'  explains  the  inten- 
sified sensitiveness  of  the  dentine  of  the  afifected  tooth. 

Of  considerable  interest  is  the  formation  in  the  pulp-chamber 
of  secondary  dentine,  always  corresponding  in  site  to  the  abraded 
surface.  In  the  chapter  on  secondary  dentine  the  statement  has 
been  made  that  mechanical  abrasion  is  a  common  cause  of  the 
formation  of  secondary  dentine.  Here  I  wish  to  draw  attention 
to  peculiar  varieties  in  the  appearance  of  secondary  dentine. 
Fig.  176  illustrates  such  a  formation  of  an  unusual  type. 
Whereas  the  upper  portion  of  the  pulp-chamber  is  filled  with 
secondary  dentine,  scantily  supplied  with  irregular  and  wavy 
canaliculi,  the  lower  portion  exhibits  a  zone  of  secondary  den- 
tine parallel  to  the  primary  dentine,  but  not  as  yet  calcified,  as 
is  proven  by  a  deep  stain  of  ammoniacal  carmin.  The  central 
portion  of  the  pulp-chamber  exhibits  an  ill-calcified  peg  of 
secondary  dentine,  with  but  scanty  canaliculi  and  granular 
deposition  of  lime-salts. 

Fig.  177  shows  peculiarities  in  the  arrangement  and  course  of 
the  dentinal  canaliculi.  In  the  uppermost  layer  the  secondary 
dentine  is  thoroughly  calcified  and  conspicuous  only  because  of 
the  bifurcation  and  the  spindle-  and  pear-shaped  widenings  of  the 
dentinal  canaliculi.     In  the  following  layer  we  see  a  formation 


312 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


of  secondary  dentine,  not  as  yet  calcified,  but  holding  a  limited 
number  of  calcareous  globules,  the  so-called  "  calco-globine."  The 
fluted  contours  within  this  layer  indicate  the  successive  forma- 


FiG.   176 

SD. 


=^"5.\\^^^\v•^Bl';^l.';/'''7^r';^J^=^ 


4mk 


Ground  Molar.    Formation  of  Secondary  Dentine  in  consequence  of   Mechanical 

Abrasion. 

PD,  primary  dentine  ;  SD,  secondary  dentine  ;  N,  non-calcified  zone  of  secondary  dentine  ; 
C,  partly  calcified  secondary  dentine.    Magnified  100  diameters. 

tion  of  the  basis-substance  in  a  manner  similar  to  the  normal 
development  of  dentine  in  a  foetus.  The  midmost  portion  of 
secondary  dentine  is  marked  by  a  devious  course  of  the  dentinal 


MECHANICAL    ABRASION. 


313 


canaliculi,  wMch,  in  the  same  field,  run  obliquely  and  trans- 
versely. Around  one  or  several  dentinal  canaliculi  we  find 
lime-salts  deposited  in  such  a  manner  that  the  nomenclature 
of  territories  which  we  have  adopted  in  our  history  of  the 
development  of  dentine  once  more  becomes  justified. 

Fig.  178  is  taken  from  another  tooth  of  the  same  patient.     It 

Fig.  177. 


«»- 


;•  ®  ©■ 


■  --J    .......  ■■WvLu.ij./., .■,,,=)■...,..*',,, ::,.i[!tt/i!i;.-(i)i:5i^ti;i:;:i:rt>;;l:!'iill 

Second ARY  Dextixe  in  Formation-.    Grouxd  Bicuspid. 

0,  calcified  secondary  dentine  with  irregalarly-widened  dentinal  canaliculi ;  iY.  non-calcified 
secondary  dentine,  deeply  stained  with  carmin,  holding  scattered  calcareous  globules ;  T,  trans- 
verse section  of  secondary  dentine  and  its  canaliculi ;  G,  calcareous  globules.  Magnified  500 
diameters. 

shows  a  successive  calcification  of  the  basis-substance  of  the 
secondary  dentine,  always  in  the  shape  of  calcareous  globules, 
partly  isolated,  partly  confluent.  The  isolated  globules  are 
mostly  pierced  by  a  dentinal  canaliculus,  which  fact  again  proves 
the  propriety  of  our  views  concerning  the  production  of  terri- 


314 


THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 


tories  around  the  dentinal  canalieuli.  A  portion  of  the  second- 
ary dentine  exhibits  branching  protoplasmic  bodies,  similar  to 
bone-corpuscles,  the  offshoots  being  in  this  instance  dentinal  canal- 
ieuli partly  in  connection  with  those  of  the  primary  dentine. 

A  rather  unusual  occurrence  is  depicted  in  Fig.  179.     The 
primary  dentine  is  succeeded  b}^  a  non-calcitied  layer  of  second- 

FiG.   178. 


Sbcondaey  Dentine  in  Formation.    Ground  Bicuspid. 

PD,  primary  dentine ;  SD.  secondary  dentine ;  N,  non-calcified  secondary  dentine  containing 
dentinal  fibers  in  bundles ;  G,  globular  deposition  of  lime-salts,  advancing  from  the  primary 
into  the  now  calcified  secondary  dentine;  B,  non-calcified  basis-substance,  holding  scattered 
calcareous  globules ;  C,  calcareous  globule  pierced  by  a  dentinal  canaliculus.  Magnified  500 
diameters. 

ary  dentine,  the  most  conspicuous  feature  of  which  is  that  its 
dentinal  canalieuli  are  arrapged  in  groups  or  bundles,  between 
which  bundles  the  basis-substance  is  altogether  devoid  of  canal- 
ieuli. This  is  followed  abruptly  by  a  layer  in  which  the  group- 
ing of  the  dentinal  canalieuli  is  shown  in  a  transverse  section. 


MECHANICAL    ABRASIOX. 


315 


Their  bundles  are  here  arranged  in  fields,  branching  and  inter- 
connecting, much  resembling  the  protoplasmic  net-work  of 
myxomatous  connective  tissue.  The  only  difference  is  that 
instead  of  the  so-called  granules,— or,  rather,  points  of  intersec- 
tion of  the  reticulum  of  living  matter  within  the  protoplasm, 
bundles   of   dentinal    canaliculi   have   appeared.     The  basis- 

FiG.  179. 

.     ...  .  ,^,   ,-  *> 


Secoxdaky  Dentine  in  Formation.    Ground  Bicuspid. 

PB,  primarj' dentine ;  iVZ,  non-calcified  secondary  dentine  in  longitudinal  section ;  iVT, 
non-calcified  secondary  dentine  in  transverse  section  ;  G,  groups  of  dentinal  canaliculi  in  trans- 
verse section  ;  P,  protoplasmic  spaces,  holding  dentinal  fibers  in  transverse  section  ;  C,  calcareous 
globule.    Magnified  500  diameters. 


substance  filUng  the  meshes  of  this  remarkable  reticulum  is 
devoid  of  canaliculi,  holding  only  a  few  scattered  calcareous 
globules.  This  specimen,  though  anomalous,  plainly  shows  the 
interchangeability  of  all  varieties  of  connective  tissue.  The 
form  may  change ;  the  type  remains. 


316  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

CHAPTER    XXVIIL    ' 

EROSION. 

This  term  is  applied  to  a  process  in  which  the  hard  dental 
tissues  are  eaten  or  wasted  away,  principally  upon  the  labial 
surfaces  near  the  cervical  margins  of  the  teeth.  Some  of  the 
older  writers  have  applied  the  name  of  denudation  to  this  pro- 
cess, but  at  present  erosion  is  universally  used.  Erosion  was 
noticed  as  early  as  1778  by  J.  Hunter;  but  the  first  investigator 
who  gave  a  reasonable  explanation  of  it  was  E.  C.  Kirk,  who, 
in  a  paper  read  before  the  First  District  Dental  Society  of  Xew 
York,  in  1886,*  demonstrated  that  its  origin  was  from  acid 
mucoid  secretions  of  the  mouth.  He,  however,  gives  the  credit 
of  prioritj^  to  J.  Truman.  Much  was  written  on  this  subject, 
but  without  advancing  anything  new,  till  E.  T.  Darby,  in  a 
paper  read  before  the  New  York  State  Dental  Society,  May, 
1892,t  stated  that  e'rosion  is  mostly  found  in  teeth  of  patients 
who  suffer  more  or  less  from  gout.  S.  G.  Perry,  in  an  article 
read  before  the  New  York  Odontological  Society,  1893,t  cor- 
roborated the  assertion  of  E.  T.  Darby,  and  proves  from  experi- 
ments made  on  himself  that  most  cases  of  erosion  yield  to  an 
anti-gout  treatment. 

In  regard  to  the  etiology  of  erosion,  there  are  three  main 
theories  :  first,  that  the  cause  is  mechanical  action  wrought  by  the 
too  frequent  use  of  the  tooth-brush  in  combination  with  gritty 
dentifrices;  second,  that  the  cause  is  local  aciditi/  of  the  mouth., 
produced  by  acid  beverages;  third,  that  it  is  constitutional  acidity 
of  the  mouth  as  produced  in  gout.  The  latter  theory  is  the  most 
generally  accepted  and  most  plausible  one,  although  we  meet 
with  many  gouty  patients  whose  teeth  are  not  affected  by  erosion. 
Again,  it  cannot  be  denied  that  by  the  too  vigorous  use  of  the 
tooth-brush  the  cementum,  the  dentine,  and  the  enamel,  espe- 
cially when  softened  by  an  acid,  may,  to  a  certain  extent,  be 
brushed  away.  But  as  we  meet  with  erosion  upon  the  approx- 
imal  and  lingual  surfaces  of  the  teeth,  the  mechanical  theory 
cannot  be  correct.     We  have  therefore  to  admit  that  erosion  is 

*  Dental  Cosmos,  1886. 

t"  Dental  Erosion  and  the  Gouty  Diathesis  :  Are  they  ITsually  Associated  ?" 
Dental  Cosmos.,  1892. 

X  "  Erosion  of  the  Teeth."      International  Dental  Journal^  1893. 


EROSIOX.  317 

not,  as  yet,  explainable  in  a  satisfactory  manner.  It  is  generally 
acknowledged  that  in  gouty  diathesis  there  exists  in  the  system 
a  superacidity,  especially  of  uric  acid.  This  acidity,  through  the 
circulation  of  the  blood,  where  it  exists  in  combination  with  other 
salts,  may  be  imparted  to  the  secretions  of  the  mouth,  in  which 
case  the  occurrence  would  be  explicable.  Gouty  conditions  of 
the  system  may  be  due  to  heredity,  or  they  may  be  produced  by 
improper  food  and  too  little  exercise  in  the  fresh  air.  S.  G. 
Perry,  in  his  article  {I.  c),  quotes  Dr.  J.  M.  Fothergill,  who  is  of 
the  opinion  that  a  gouty  diathesis  of  the  system  depends  upon 
imperfect  conditions  of  the  liver.  Dr.  Fothergill  distinguishes 
two  kinds  of  gout:  one,  when  a  person  who  has  lived  too  luxu- 
riously for  a  number  of  years  gets  rich  man's  gout;  the  other, 
when  a  person  born  with  an  imperfect  liver,  and  not  taking 
exercise  enough  in  the  fresh  air  to  consume  even  a  small  quan- 
tity of  nitrogenized  food,  gets  poor  man's  gout.  The  writer  him- 
self has  observed  patients  who  suffer  from  both  kinds  of  gout, 
and  who  state  that  whenever  their  teeth  become  sensitive  they 
know  that  they  are  about  to  have  an  attack  of  this  disease.  On 
the  other  hand,  I  know  of  quite  a  number  of  patients  who  suffer 
from  gout,  but  their  teeth  do  not  show  erosions.  This  theory, 
therefore,  although  plausible,  is  by  no  means  a  finality.  So  much 
is  certain,  however :  that  erosion  is  due  to  the  action  of  an  acid, 
— probably  lactic  acid.  It  was  also  supposed  that  the  living 
matter  of  the  tooth  could  produce  the  reaction;  but  as  both 
living  and  devitalized  teeth  are  affected  in  a  similar  manner  by 
this  destructive  process,  this  theory  is  not  tenable. 

There  are  a  number  of  cases  on  record  of  chemical  abrasion,  so 
termed,  of  which  the  writer  has  seen  two  in  his  own  practice. 
Both  had  the  characteristics  of  erosion,  although  the  labial  sur- 
faces of  the  teeth  showed  but  little  of  this  process,  while  the 
cutting-edges  of  the  incisors  and  cuspids,  especially  the  upper 
ones,  were  more  than  half  dissolved  away.  The  teeth  were 
similar  in  appearance  to  those  affected  by  mechanical  abrasion, 
but  as  the  lower  teeth  did  not  articulate  with  the  upper  ones, 
mechanical  abrasion  in  their  case  was  out  of  the  question. 

In  regard  to  the  pathological  anatomy  of  erosion,  there  is  but 
little  to  say.  As  the  appearances  of  the  eroded  dental  tissues 
under  the  microscope  are  similar  to  those  affected  by  mechanical 
abrasion,  I  refer  the  reader  to  Chapter  XXYII,  in  which  that 
topic  is  considered. 


318  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

Erosion  mostly  appears  in  persons  over  thirty  years  of  age, 
and  starts  in  one  or  more  small  pits,  or  a  sliglit  groove  near 
the  cervical  margin,  in  tlie  cement  of  the  neck  of  the  tooth. 
Usually  the  attack  is  upon  the  labial  surfaces;  sometimes  it  is 
noticed  upon  the  approximal  surfaces;  but  quite  rarely  on  the 
liug-ual  surfaces  of  the  teeth.  The  eroded  places  mostlv  are 
smooth,  and  have  a  polished  appearance.  Often  these  grooves 
start  in  the  enamel  of  the  labial  surfaces  of  the  teeth,  a  little 
distance  away  from  the  gum,  presenting  a  single,  or  sometimes 
a  double,  furrow  which  runs  parallel  to  the  cutting-edges  of  the 
teeth.  In  rare  instances,  we  notice  the  greater  portion  of  the 
enamel  of  the  labial  surfaces  of  the  incisors  dissolved.  All  the 
eroded  surfaces  are  sharply  defined ;  that  is,  the  boundary  is 
surrounded  by  a  sharp  border,  whether  of  enamel  or  cementum. 
We  also  meet  with  eroded  surfaces,  the  outlines  of  which,  under 
the  microscope,  look  fluted  or  slightly  bay-like.  This  appear- 
ance has  induced  some  writers  to  believe  that  the  destructive 
agent  of  erosion  was  the  so-called  Hoicskq/s  lacunce,  or  giant-cells. 
These  fluted  outlines  are  mostly  found  in  ill-calcified  teeth,  and 
again  prove  that  the  dentine  and  the  cementum  are  dissolved  in 
the  same  manner  in  which  they  are  built  up, — i.e.,  by  territories. 
Erosion  usually  commences  on  the  upper  or  lower  cuspids, 
probably  because  these  teeth  are  generally  the  first  that  sufier 
from  recession  of  the  gums.  It  has  been  stated  that  erosion 
occurs  below  the  margin  of  the  gum,  but  the  writer  has  not 
met  with  a  single  case  in  which  erosion  was  not  preceded  by  a 
corresponding  recession  of  the  gum.  Although  there  are  cases 
of  erosion  which  are  seen  to  extend  beneath  the  gum-margin, 
in  these  instances  we  always  notice  an  inflammation  which  has 
produced  a  slight  tumefaction  of  the  gingival  border,  thereby 
overlapping  the  eroded  surface.  The  cuspids  occupy  the  most 
prominent  position  in  the  dental  arch,  and  consequently  are  the 
most  subject  to  irritation  by  the  tooth-brush,  which  probably 
accounts  for  the  early  recession  of  the  gums  on  the  labial  sur- 
faces of  these  teeth.  The  next  teeth  aftected  by  erosion  are 
most  commonly  the  first  and  second  bicuspids ;  then  the  in- 
cisors ;  and,  lastly,  but  not  often,  the  molars.  When  erosion 
has  affected  most  of  the  teeth  in  the  dental  arch,  usually  the 
cuspids,  and  especially  the  upper  ones,  contain  the  deepest 
defects ;  next  the  bicuspids ;  and  then  the  incisors ;  while  the 
defects  upon  the  buccal  surfaces  of  the  molars  are  rarely  large. 


EROSIOX. 


319 


As  the  eroded  surfaces  increase  in  extent,  they  assume  an  ap- 
pearance as  though  they  had  been  made  by  means  of  a  small 
three-cornered  or  round  lile.  (See  Fig.  180.)  The  surfaces  are 
generally  smooth  and  bright,  but  in  some  few  cases  dull  and 
rouffh.  The  roug-hness  usually  is  due  to  the  commencement  of 
caries.  The  color  of  the  eroded  tissues,  at  first,  is  white  or 
yellowish-white  in  the  enamel,  and  a  light  yellow  in  the  dentine 
and  the  cementum;  but  later  on  it  changes  in  the  latter  two 
tissues  to  a  dark  yellow  or  even  dark  brown.     The  eroded  sur- 


FlG.    1 


Geouxd  Section  of  ax  Upper  Lateral  Ixcisor,  with  Erosiox. 
E.  erosion  at  the  labial  aspect  of  the  neck.    Magnified  4  diameters. 

faces  are  usually  soon  discovered  by  the  patient,  especially 
during  the  act  of  brushing  the  teeth,  or  when  a  foreign  sub- 
stance, such  as  a  tooth-pick,  a  pin,  or  the  nail  of  a  finger,  is 
brought  in  contact  with  the  erosion.  "When  this  process  is 
active,  tbe  affected  dentine,  the  cementum,  and  sometimes  tbe 
enamel  are  extremely  sensitive ;  while  as  soon  as  tbe  secretions 
of  the  mouth  attain  a  neutral  or  an  alkaline  reaction,  the  eroded 
surfaces  lose  their  sensitiveness,  and  tbe  process  comes  to  a 
standstill. 


320  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

Erosion,  therefore,  cannot  be  arrested  by  the  introduction  of 
filhng-materials  into  the  eroded  cavities ;  on  the  contrary,  we 
frequently  observe  the  gold  fillings  in  the  cervical  portions  of 
the  teeth  stand  above  the  level  of  the  enamel  for  a  considerable 
height.  In  some  instances,  however,  the  eroded  surfaces  become 
attacked  by  caries,  in  which  case  the  filling  of  these  places 
becomes  a  necessity.  As  stated  above,  when  the  eroded  surfaces 
begin  to  decay,  we  first  notice  a  roughness,  and  afterward  a 
softening,  which  is  characteristic  of  caries.  When  the  carious 
process  is  an  acute  one,  the  color  of  the  eroded  surfaces  may 
remain  yellowish-white  or  even  white,  and  in  these  cases  caries 
is  apt  to  be  confounded  with  erosion.  In  the  majority  of  in- 
stances, however,  the  caries  preceded  by  erosion  is  of  a  dark- 
yellow  or  a  brown  color,  and  not  easily  mistaken  for  erosion. 


CHAPTER    XXIX. 

THE   REACTION  OF  THE  DENTINE  UPON  FILLINGS. 

Ddring  the  past  sixteen  years,  for  the  purpose  of  procuring 
trustworthy  data  as  to  the  reaction  of  various  filling-materials 
upon  the  hard  tissues  of  the  teeth,  I  have  made  a  number  of 
experiments  in  their  introduction,  mainly  upon  the  temporary 
teeth  of  my  own  sons.  Accurate  notes  as  to  conditions  and 
dates  were  kept,  so  that  the  history  of  each  experiment,  includ- 
ing the  time  the  filling  remained  in  the  cavity,  was  complete. 
I  came  into  possession,  also,  of  a  number  of  teeth  from  patients, 
into  which  fillings  had  been  introduced  on  account  of  caries  in 
the  ordinary  course  of  my  practice.  Altogether,  there  were 
somewhat  more  than  fifty  teeth,  of  each  of  which  I  knew  the 
exact  history. 

Some  of  these  teeth  were  ground  into  thin  slabs  under  the 
precautions  mentioned  in  the  chapter  on  dentine,  the  most  im- 
portant of  which  is  not  to  allow  the  slab  to  become  dry,  even 
for  a  moment,  during  the  process  of  grinding.  Others  were 
placed  in  a  one-half  of  one  per  cent,  solution  of  chromic  acid, 
which  was  renewed  daily  for  about  one  week.  These  teeth 
were  kept  for  several  years  in  separate  jars,  the  solution  being 


THE    REACTION    OF    THE    DENTINE    UPON    FILLINGS.  321 

changed  about  three  times  a  year.  For  some  time,  about  two 
weeks  before  cutting,  the  one-half  of  one  per  cent,  solution  of 
chromic  acid  was  renewed  daily,  at  the  end  of  which  time  the 
teeth  had  become  softened  so  as  to  be  fit  for  cutting  with  the 
microtome. 

The  deeper  layers  of  the  dentine  needed  decalcification  in 
most  cases,  even  after  imbedding  in  celloidin. 

The  protracted  exposure  to  the  decalcifying  agent  eflected  a 
surprising  result  upon  the  enamel-tissue,  for,  w^hereas  in  pre^ 
vious  years  I  had  invariably  met  wdth  failure  in  decalcifying 
this  tissue,  I  now  succeeded  in  decalcifying  the  enamel  of  both 
temporary  and  permanent  teeth. 

Many  of  my  specimens  show  varying  spaces  of  thorough  de- 
calcifi-cation,  but  it  never  involves  the  enamel  m  toto.  What  I 
have  stated  with  res-ard  to  the  structure  of  enamel-tissue  in 
Chapter  XI,  I  found  corroborated  in  these  specimens,  made 
for  an  entirely  different  purpose  from  those  of  former  experi- 
ments. The  mere  fact  that  enamel  can  be  partially,  at  least, 
decalcified  and  preserved,  shows  plainly  the  error  in  the  view 
still  held  by  some,  that  enamel  is  not  a  tissue,  but  a  coat  of 
mail  entirely  destitute  of  properties  of  life. 

In  analyzing  the  results  of  fillings,  I  wish  to  draw"  attention 
to  several  possible  sources  of  error  which  must  constantly  be 
borne  in  mind  to  prevent  faulty  conclusions.  First,  it  is  not 
always  easy  to  determine  the  exact  location  of  the  previous  fill- 
ing at  the  border  of  the  cavitj^,  since  cre^uces  sometimes  appear 
in  the  margin  of  an  aspect  resembling  that  of  a  previously- 
filled  cavity.  The  border  of  the  dentine  is,  as  a  rule,  easily 
recognizable  by  the  presence  of  a  film  of  enamel,  or,  where 
this  is  missing,  by  the  bay-like  excavations  present  in  the  inter- 
zonal layer  between  dentine  and  enamel.  A  second  source  of 
mistake  is  the  presence  of  portions  of  dentine  decalcified  before 
being  placed  in  the  chromic-acid  solution.  Such  fields,  in 
specimens  stained  with  an  ammoniacal  solution  of  carmin,  are 
recognizable  by  a  green  color,  which  is  due  to  the  reduction  of 
the  chromic  acid  to  chromic  oxide.  It  is  considered  a  legitimate 
procedure  to  introduce  fillings  into  ca^uties  in  the  dentine  even 
though  the  deeper  portions  of  the  cavity  be  slightly  discolored,, 
rather  than  to  expose  a  pulp.  Moreover,  small  carious  places 
in  the  dentine  or  enamel  cannot  always  be  detected  in  a  cavity 
of  a  tooth  with  the  naked  eye,  or  even  with  a  simple  magnif\dng 

22 


322 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


lens.  In  such  a  case,  under  the  microscope,  the  impression 
may  he  conveyed  to  the  ohserver  that  he  sees  reaction  pro- 
cesses in  the  dentine  where,  in  fact,  only  yestiges  of  the  pre- 
yious  process  of  caries  are  present.  F,  B,  Fig.  181,  affords  an 
iUustration  of  this  statement.  Along  the  horder  of  a  cavity 
of  the  tooth  which  was  filled  with  gold  April  22,  1889,  and  ex- 
tracted on  account  of  pericementitis  April  26,  1893,  a  process 
is  seen,  which  was  first  descrihed  hv  Ahhott  as  inflammation 


Amelitis — Inflammation  of  Enamel  at  the 


B,  border  of  cavity  ;  F,  prisms  broken  up  to  medullary  corpuscles,  enamel-fibers  enlarged. 
Magnified  500  diameters. 


of  the  enamel,  amelitis,  due  to  caries.  The  enamel-prisms  are 
broken  up  into  small  squares,  or  reduced,  as  it  were,  to  their 
embryonal  state.  More  than  that,  the  enamel-fibers  between 
the  broken-up  prisms  are  slightly  enlarged.  I  cannot  reason- 
ably attribute  this  change  to  the  presence  of  the  gold  filling, 
since  not  even  dentine  shows  so  pronounced  a  reaction  after 
the  introduction  of  £:old  fillinsfs. 


THE    REACTION    OF    THE    DENTINE    UPON    FILLINUS.  323 

There  are  two  possible  explanations  of  the  amelitis  in  this 
case :  either  we  have  before  us  vestiges  of  primary  caries  of  the 
enamel,  or  the  enamel  has  been  attacked  by  secondary  caries. 

A  third  source  of  error  is  found  in  the  fact  that  practitioners 
commonly  apply  to  the  walls  of  an  excavated  ca^dty  strong 
aseptic  coagulants,  such  as  pure  carbolic  acid,  creasote,  a  solu- 
tion of  corrosive  sublimate,  etc.,  before  introducing  the  filling. 
Thus  the  tissues  along  the  border  of  the  cavity  are  rendered 
dead  to  a  certain  depth.  This  is  shown,  under  the  microscope, 
by  a  green  color  along  the  border  of  the  cavity  and  a  shriveled, 
granular  appearance  of  the  dentinal  fibers  to  a  certain  depth  of 
the  tissue,  when  normal  fibers  again  reappear.  That  under 
these  conditions  no  reaction  of  the  filling-material  can  be  ex- 
pected along  the  border  of  the  cavity  is  plain  enough. 

Having  enumerated  the  points  to  be  kept  in  view,  I  now  pro- 
ceed to  the  analysis  of  the  specimens. 

I.  Gutta-percha. — This  never  showed  the  slightest  reaction  at 
the  border  of  the  cavity  in  the  dentine.  The  dentinal  canaliculi 
and  their  tenants  terminate  abruptly  toward  the  ca^uty.  Only 
here  and  there  was  seen  a  green  discoloration  at  the  border, — 
dne,  probably,  to  coagulants  applied  before  the  introduction  of 
the  filling. 

II.  Gold. — In  some  instances  no  reaction  was  noticeable  in 
the  dentine,  only  a  zone  of  green  color,  attributable  to  causes 
just  mentioned  under  gutta-percha.  In  other  instances,  there 
is  a  distinct  reaction  along  the  border,  as  illustrated  in  Fig.  182. 
The  dentine  is  so  thoroughly  consolidated  in  the  zone  nearest 
the  cavity  that  this  portion  shows  no  dentinal  canaliculi.  The 
latter  stop  short,  the  termination  being  evidently  due  to  an  ob- 
literation of  the  canaliculi,  at  first  partial  and  finally  complete. 
The  solidified  zone  of  dentine  is  still  alive,  iudoino;  from  the 
slight  stain  present  of  the  amiuoniacal  solution  of  carmin. 
In  still  other  instances  the  gold  filling  has  led  to  a  partial  ob- 
literation of  dentinal  canaliculi  similar  to  that  induced  by  oxy- 
phosphate  of  zinc,  though  never  as  complete  as  that  which 
follows  the  introduction  of  the  last-named  fiUino^-material. 

III.  Oxyphosphate  of  Zinc. — The  reaction  is  almost  constantly 
present,  and  consists  of  a  solidification  of  the  dentine  and  an 
obliteration  of  a  number  of  dentinal  canaliculi.  The  dentinal 
canaliculi  which  are  obliterated  under  oxyphosphate  fillings 
first  become  faint,  scarcely  traceable,  and  ultimately  disappear. 


324 


THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


in  consequence  of  which  disappearance  the  fiehls  of  basis- 
snbstance  between  the  dentinal  canaliculi  are  considerably 
broadened. 

The  ramifications  of  some  of  the  dentinal  canaliculi  seen  in 
Fig.  183  are  made  explicable  by  the  presence  of  lateral  oiFshoots 


Fig.  18-2. 


s^^e^^ 


\:\P^ 


m\\\ 


^^lIBi 


■I!  lira 


iiiUlhiiMniMimiliuiiiiiilnmli 

Permanent  Tooth,  Previously  Filled  with  Gold. 

-B.  border  of  cavity,  overspread  with  debris  of  dentine ;  S,  zone  of  consolidation  ;  JD,  normal 
dentine.    Magnified  500  diameters. 

of  the  dentinal  fibers,  some  of  which  become  conspicuous  in 
consequence  of  irregularity  in  the  process  of  consolidation. 
The  consolidation  is  densest  along  the  border  of  the  cavity, 
where  dentinal  canaliculi  are  quite  scanty;  but  the  consolidated 
dentine  extends  to  a  considerable  depth  before  it  blends  with 
normal  dentine. 


THE    REACTION    OF    THE    DENTINE    UPON    FILLINGS. 


325 


IV.  Amalgam. — The  features  that  appear  after  the  introduc- 
tion of  this  filling  depend  upon  the  length  of  time  the  material 
is  left  in  the  cavity.     A  few  months  after  its  introduction  a 


Fig.  183. 


GrEOUND  Bicuspid,  Previously  Filled  with  Oxyphosphate  of  Zinc. 

B,  border  of  ca-vity ;  D,  normal  dentinal  canalieuli ;    0,   obliterated  dentinal  oanaliculi. 
Magnified  500  diameters. 


pronounced  discoloration  of  the  border  of  the  cavity  is  almost 
invariably  visible.  This  is  due  to  the  penetration  of  silver  or 
mercuric  sulphide  into  the  dentinal  canalieuli.     The  metallic 


326 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


particles  are  black  under  tlie  microscope,  and  therefore  easily 
recognizable.  Tliey  seem  to  be  carried  into  the  depths  of  the 
dentine  for  some  distance,  by  contractions  of  the  dentinal  fibers  ; 
otherwise  it  would  be  inexplicable  that  the  most  deeply-stained 
discoloration  is  seen  at  some  distance  away  from  the  border  of 
the  cavity.     (See  Fig.  184.) 

Fig.  184. 


Ground  Tooth,  Previously  Filled  with  Amalgam. 

S,  surface  of  filled  cavity  marked  by  large  metallic  clusters  ;  B,  dentinal  canaliculi  holding 
rows  of  metallic  particles,  the  reticulum  quite  pronounced  in  a  few  places  ;  P,  darkly  pigmented 
zone  ;  L,  slightly  pigmented  portion  of  dentine,  followed  by  a  darker  pigmented  portion  farther 
below.    Magnified  500  diameters. 


The  accumulation  of  the  metallic  granules  is  sometimes  an 
excellent  means  of  rendering  visible  the  minute  structure  of 
the  dentine.  In  the  highest  degree  of  infiltration  not  only  the 
dentinal  fibers  and  their  coarser  offshoots,  but  also  the  finest 


THE    REACTIOX    OF    THE    DENTIXE    UPON    FILLINGS. 


327 


reticulum  of  tlie  living  matter  in  the  basis-substance  is  strongly 
defined  in  black.  In  Figs.  51  and  52,  in  the  chapter  on  "  The 
Minute  Structure  of  Dentine,"  this  ett'ect  upon  the  reticulum  is 
illustrated.  Discoloration  after  the  introduction  of  amalgam 
becomes  less  noticeable  in  the  vicinit}'  of  the  cavity  in  propor- 


FiG.   185. 


Decalcified  Temporary  Tooth,  Previously  Filled  tvith  Amalgam. 

B,  border  of  cavity ;  D,  dentinal  canaliculi  of  varying  calibers,  holding  metallic  granules;  R, 
reticulum  in  the  basis-substance  ;  C,  broad  fields  of  recalcified  basis-substance.  Magnified  500 
diameters. 

tion  to  the  lapse  of  time  after  its  introduction.  On  the  other 
hand,  the  body  of  the  tooth  in  time  assumes  a  dark  hue.  This 
fact  becomes  explicable  when  we  recognize  the  gradual  diffusion 
of  the  metallic  particles  throughout  the  dentine.  Tin  fillings 
behave  similarly  to  amalgam,  only  in  a  less  pronounced  degree. 


328  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

After  the  lapse  of  several  years  the  reaction  of  amalgam  upon 
the  adjacent  dentine  is  quite  marked.  It  consists  in  a  consoli- 
dation of  the  dentine,  due  to  a  partial  obliteration  of  the  den- 
tinal canaliculi  and  a  simultaneous  broadening  of  the  fields  of 
the  basis-substance.     (See  Fig.  185.) 

The  apparently  devious  courses  of  some  of  the  dentinal 
canaliculi  become  comprehensible  upon  the  grounds  stated  in 
the  paragraph  concerning  oxj^Dhosphate  of  zinc.  Some  of  the 
lateral  coarse  oiFshoots  of  the  dentinal  canaliculi  have  been 
made  conspicuous  by  the  preceding  decalcification,  and  have 
remained  unchanged,  though  many  of  the  main  canaliculi  or 
portions  of  them  have  become  obliterated.  That  the  recalcifica- 
tion  is  not  a  perfect  one  is  best  evidenced  by  the  varying  cali- 
bers of  the  dentinal  canaliculi  and  the  presence  of  the  delicate 
reticulum  of  living  matter  in  the  basis-substance,  which  is  the 
more  conspicuous  the  nearer  it  approaches  to  the  border  of  the 
cavity.  All  the  formations  of  living  matter  in  such  specimens 
— the  dentinal  fibers  as  well  as  the  minutest  reticulum — contain 
tiny  particles  of  sulphuretted  metal,  though  nowhere  in  large 
numbers. 

From  the  above  facts  we  may  draw  the  following  practical 
conclusions :  For  all  teeth  in  which  the  hard  tissues  are 
much  softened,  owing  to  constitutional  difficulties,  and  where 
irritation  of  the  living  matter  is  to  be  prevented,  gutta-percha 
T\dll  prove  to  be  the  best  filling-material.  Oxj^phosphate  of  zinc 
will  be  found  preferable  in  fairl}^  good  teeth  which  have  become 
softened  through  caries  or  temporary  illness.  Gold  produces  a 
reaction  in  the  dentine  in  some  instances;  in  others  it  does  not. 
It  is  best  adapted  for  adult  and  well-calcified  teeth.  Amalgam 
ought  to  be  used  in  exceptional  cases  only.  Although  these 
rules  may  hold  good  for  general  practice,  in  the  majority  of 
instances  the  practitioner  must  be  guided  by  the  circumstances 
of  the  case  and  his  own  experience.  It  is  important,  however, 
to  remember  the  fact  that  the  application  of  pure  carbolic  acid 
mummifies,  so  to  speak,  the  living  matter  in  the  dentine  of  the 
cavity  to  a  slight  depth.  This  action  will  render  the  dentine 
less  sensitive  to  thermal  changes,  and  make  the  walls  of  the 
cavity  aseptic. 


HYPEROSTOSIS    OF    ROOTS    OF    TEETH.  329 

CHAPTER  XXX. 

HYPEROSTOSIS  OF  ROOTS  OF  TEETH.* 

"Under  the  term  hyperostosisf  I  propose  to  consider  all  the 
forms  of  pathological  new  growths  of  ceiyentum,  mcluding  what 
authors  are  wont  to  term  osteoma,  exostosis,  hypertrophy  of  the 
cement,  etc. 

"As  to  the  cause  of  this  not  very  infrequent  disease,  the 
following  points  may  be  enumerated  : 

"  A.  Direct  irritation  of  the  pericementum  through  slight 
long-standing  caries  of  the  crown  or  neck;  or,  exposure  of  the 
pulp,  mainly  the  result  of  caries ; 

"  B.  Localized  irritation  of  the  pericementum  of  constitutional 
origin,  such  as  from  gout  and  syphilis ; 

"  C.  Irritation  of  the  pericementum  of  upper  teeth  after  the 
removal  of  their  antagonizing  teeth  of  the  lower  jaw,  the  result 
of,  or  induced  by,  gravitation. 

"  Obviously,  irritation  of  the  pericementum  is  considered  by 
all  authors  as  the  cause  of  outgrowths  of  cementum. 

"  That  a  chronic  irritation  of  the  pericementum,  whatever  the 
cause  maybe,  may  result  in  a  new  formation  of  cementum,  no- 
body will  doubt;  nay,  it  has  been  clearly  proven  by  Bodecker 
that  a  circumscribed  hyperostosis  of  the  cementum  may  arise 
from  chronic  pericementitis.  The  question,  however,  is.  Can 
a  diffused  enlargement  of  the  cementum  occur  in  consequence 
of  pericementitis,  either  of  a  local  or  constitutional  origin,  after 
the  cementum  has  once  been  fully  formed  ?  This  question  I 
feel  constrained  to  answer  in  the  negative,  and  I  base  my  opinions 
upon  microscopical  studies  of  such  tumors.  My  conviction  is 
that  hyperostosis  of  cementum  of  a  diffused  character  is  in  most 
instances  a  fmtal  malformation . 

"  If  a  carious  tooth  be  extracted,  and  the  roots  be  found  in  a 
hyperplastic  condition,  the  first  impression,  of  course,  would  be 
that  the  inflamed  pu^lp,  in  this  case,  has  led  to  pericementitis, 
and  the  latter  to  hyperostosis  of  the  roots.     This  undoubtedly 

*  Extract  from  an  article  by  Frank  Abbott.     Dental  Cosmos,  1886. 

t  L.  A.  Weil,  in  an  article,  "  Ueber  Ceraent-hyperplasie, "  Oest.-Ung.  Viertel- 
jahrschrf.  Zahnheilkunde,  III  Jalirg.,  Heft,  ii,  remarks  that  the  term  "hyperos- 
tosis" would  imply  a  iiniform  and  flat  increase  of  bone-tissue,  whereas  "exos- 
tosis" means  a  circumscribed  new  formation  of  this  tissue.  He  prefers  the  term 
•"  hyperplasia  of  cementum"  for  the  designation  of  all  forms  of  hyperostosis. 


330  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

in  some  instances  may  be  the  case,  more  especially  when  the 
process  of  caries  has  attacked  a  lateral  surface  of  the  crown  or 
the  neck  of  a  molar,  and  the  root  or  roots  nearest  to  the  point 
of  irritation  of  the  pulp  are  found  to  be  enlarged ;  but  if  all 
the  roots  of  a  molar  are  uniformly  enlarged,  or  fused  together, 
we  hardly  feel  justified  in  stating  that  caries  was  the  primary 
and  hyperostosis  of  the  roots  the  secondary  cause,  or  the  result 
of  such  a  primary  cause  ;  for  it  is  possible  that  the  hyperplasia 
of  the  roots  has  been  present  long  before  the  caries  made  its 
appearance.  The  latter  assumption  becomes  almost  a  certainty 
when,  upon  grinding  such  teeth  for  microscopical  research,  we 
find  either  that  the  caries  has  not  penetrated  sufficiently  deep  to 
cause  inflammation  of  the  pulp,  or  the  dentine  is  found  in  a 
condition  which  could  not  be  the  result  of  simple  '  eburnitis,' 
but  can  have  been  the  result  only  of  a  malformation  at  the 
beginning  of  its  growth  in  fcetal  life. ' 

"  After  a  careful  study  of  a  large  number  of  examples  of  hyper- 
ostosis, I  feel  entitled  to  make  the  statement  that  the  teeth  ex- 
hibiting it  were  sound  and  their  pulps  alive  at  the  time  the  bony 
growth  had  formed. 

"Whenever  a  tooth  becomes  deprived  of  its  nourishment  from 
the  pulp,  I  doubt  the  possibility  of  an  osseous  new  formation 
upon  the  cementum;  and,  further,  should  such  a  new  formation 
have' existed  previously,  its  grow^th  has  undoubtedly  ceased  the 
moment  the  life  of  the  pulp  was  gone.  Should  a  dentist  extract 
a  sound-looking  tooth  to  relieve  excessive  pericementitis,  or 
neuralgia  suspected  to  arise  from  pericementitis,  and  find  the 
root  or  roots  considerably  enlarged,  he  would  hardly  be  justified 
in  concluding  that  the  pericementitis  and  neuralgia  had  caused 
the  growth  upon  the  roots;  but,  on  the  contrary,  he  would 
naturally  conclude  that  the  growth  had  been  the  primary  feature 
and  the  pericementitis  and  neuralgia  secondary  features  of  the 
disease.  If,  for  instance,  to  relieve  neuralgia,  there  be  removed 
from  one  upper  jaw  a  large  number  of  sound-looking  teeth,  the 
roots  of  all  of  which  are  found  to  be  considerably  enlarged,  we 
conclude  that  these  roots  were  malformed  at  the  earliest  stage 
of  their  development.  I  have  in  my  possession  six  upper  molars, 
all  removed  from  the  same  person's  mouth,  to  relieve  neuralgia. 
The  roots  of  all  of  them  are  more  or  less  enlarged ;  three  have 
no  decay  whatever  in  their  crowns,  and  the  other  three  are  but 
slightly  aflfected. 


HYPEROSTOSIS    OF    ROOTS    OF    TEETH.  331 

"Xo  growth  of  any  tissiie  is  possible  without  its  being  first 
partially  reduced  to  medullary  elements.  An  augmentation  of 
the  cementuni  is  impossible  without  a  preceding  augmentation 
of  the  medullary  tissue,  which  again  is  caused  by  increased 
nutrition,  or,  as  it  is  generally  expressed,  an  irritation. 

"  I  propose  to  show  that  cementum,  in  a  pathological  (hyper- 
plastic) condition,  is  endowed  with  properties  of  life  the  same 
as  in  a  normal  state.  Thus  it  becomes  explicable  that  hyper- 
plastic cementum  itself  may  become  the  subject  of  pathological 
processes,  particularly  of  inflammation.  Hyperplastic  cementum 
may,  and  often  does,  become  partially  destroyed  by  cementitis 
and  transformed  into  medullary  tissue,  from  which,  evidently, 
an  additional  new  growth  of  cementum  may  start. 

"  Since  the  beginning  of  the  present  century,  a  good  many 
reliable  observers  have  described  and  depicted  anomalous  teeth 
with  liy23erostosi8  in  varying  degrees  of  development.  Some  of 
these  illustrations  are  striking  examples  of  the  excessive  growths 
to  which  cementum  may  attain,  and  still  be  tolerated  by  the 
sufferer.  All  observers  and  clinicians,  I  think,  agree  that  this 
disease  attacks  bicuspids  and  molars  only,  incisors  and  cuspids 
appearing  to  be  exempt;  and,  again,  the  teeth  of  the  upper  jaw 
are  more  frequently  affected  than  those  of  the  lower. 

"  Facial  neuralgia  of  the  most  severe  and  unvieldino;  char- 
acter  is  frequently  caused  by  these  malformations.  At  the  same 
time,  the  symptoms  which  point  to  a  diagnosis  of  hyperostosis 
of  the  roots  are  not  very  marked.  When  observable  at  all, 
they  consist  of  a  slight  continued  uneasiness  in  the  jaw  (as 
sometimes  expressed  by  a  patient,  '  I  can't  call  it  real  pain,  but 
I  am  constantly  aware  that  I  have  a  tooth  in  that  locality').  It 
is  akin  to  pain,  with  slight  soreness  of  the  tooth  or  teeth  upon 
biting,  while  excessive  pressure  upon  it  in  any  direction  is  pro- 
ductive of  quite  severe  and  prolonged  pain.  Eventually  the 
soreness  becomes  more  marked,  and  the  pain  constant  or  inter- 
mittent, and  finally  terminates  in  possibly  an  abscess,  severe 
mental  derangement,  or  the  removal  of  the  tooth  as  a  cure. 

"  It  is  not  infrequently  the  case  that  a  patient  suffering  from 
neuralgia  applies  to  a  dentist  to  have  a  certain  tooth  extracted 
for  relief,  the  case  being  to  the  dentist  so  obscure  that  he  takes 
the  patient's  word  for  it,  and  extracts  the  tooth ;  but  to  his  dis- 
gust the  patient,  after  a  few  moments,  turns  to  him  and  says, 
'  Why,  doctor,  that  isn't  the  tooth;  the  pain  is  just  as  bad  as  it 


332 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


was  before  yon  took  it  out.'  This  operation  is  repeated  over 
and  over  again  with  the  same  result,  until  finall}^,  perhaps,  it  is 
the  last  tooth  in  the  jaw  which  when  taken  out  reveals  the 
cause  of  this  long  suffering,  in  a  root  or  roots  enlarged  from 
hyperostosis.  A  peculiar  feature  in  these  cases  is  the  long-con- 
tinued and  most  distressing  pain  that  follows  such  extractions, 
relief  coming  but  very  slowly. 

"As  custodian  of  that  portion  of  the  museum  of  the  !N"ew 
York  College  of  Dentistry  which  pertains  to  my  department, 
I  have  come  into  possession  of  seventy  odd  teeth  exhibiting 
hyperostosis  of  the  roots,  and  this  comparatively  large  number 
prompts  me  to  try  to  classify  the  different  varieties  as  they  occur 
to  me.  I  will  here  add  that  about  one-third  of  these  teeth  are 
sound  or  very  nearly  so.  Previous  authors  have  simply  de- 
scribed different  forms,  more  or  less  striking,  without  observ- 
ing any  system  in  the  arrangement. 


Fig.   U 


Fig.   187. 


"  I.  Circumscribed  Hyperostosis.— Under  this  title  are  included 
osteoma  and  exostosis  of  the  authors,  which  are  characterized 
by  an  outgrowth  of  bone-tissue  from  the  cementum,  of  a  limited 
size,  varying  from  that  recognizable  only  with  the  microscope 
to  that  of  a  lentil  or  a  pea.  Their  surfaces  usually  present  a 
nodular  appearance,  and  sometimes  they  are  adjacent  to  newly- 
formed  cancellous  structure  of  bone,  evidently  caused  by  osteitis 
of  the  socket.     I  would  subdivide  this  group  into  : 

"  A.  Osteoma  on  the  body  of  the  root  (Fig.  186,  a,  b). 

"  B.  Osteoma  on  the  apex  of  the  root  (Fig.  187,  a,  b). 

"Either  of  these  appears  mostly  upon  teeth  the  crowns  of 
which  are  more  or  less  destroyed  by  caries,  with  probably  a 
long-standing  exposed  pulp,  which  plainly  indicates  that  their 
cause  is  likely  to  be  accounted  for  in  localized  pericementitis 
from  this  source.    If,  however,  we  bear  in  mind  that  the  destruc- 


HYPEROSTOSIS  OF  ROOTS  OF  TEETH.  333 

tion  of  the  life  of  the  pulp  prevents  or  stops  the  formation  of 
osteoma  on  the  roots,  we  must  come  to  the  conclusion  that  such 
tumors  had  commenced  their  formation  long  before  the  exposure 
of  the  pulp,  or  this  must  have  remained  alive  for  a  very  long  time 
after  its  exposure  before  it  died,  causing  during  this  long  time 
a  slight  but  constant  irritation,  transferred  to  the  pericementum. 

"As  soon  as  severe  pericementitis  from  an  exposed  pulp  sets 
in,  unless  vigorous  steps  for  its  relief  are  taken,  the  pulp  is  in 
a  fair  way  to  become  lifeless  very  soon.  After  its  death  severe 
pericementitis  and  its  distressing  terminations  are  too  well 
known  to  practitioners  to  need  mentioning  here.  In  neither  of 
the  latter  instances  would  we  expect  a  bony  outgrowth  on  the 
roots.  It  is,  in  my  judgment,  only  an  irritation  of  the  perice- 
mentum while  the  pulp  is  living  that  can  result  in  an  increased 
cementum. 

"  In  some  persons,  or  conditions  of  persons,  a  very  superiicial 
decay,  more  particularly  upon  the  necks  of  teeth,  will  produce 
marked  pericementitis  and  neuralgia.  We  may  infer  from  this 
fact  that  in  other  persons  or  conditions  (or  possibly  the  same), 
perhaps  under  the  influence  of  constitutional  disturbances,  a 
local  irritation  of  the  pericementum  is  induced,  causing  exos- 
tosis, long  before  exposure  of  the  pulp. 

"II.  DifFused  Hyperostosis  with  Roots  Separated. — Under 
this  heading  a  large  number  of  specimens  of  my  collection 
may  be  summed  up,  either  of  otherwise  sound  teeth  or  those 
decayed  or  filled.  In  relation  to  what  I  have  stated  before,  I  will 
admit  that  pericementitis  from  caries  is  a  cause  of  hyperostosis 
only  when  one  root,  or  two,  are  involved,  others  being  in  a 
normal  condition,  and  the  enlarged  root  or  roots  corresponding 
to  the  carious  canity  either  on  the  neck  or  crown  of  the  tooth. 
AYhen  all  the  roots  of  molars  are  atfected,  mthout  the  least 
symptom  of  disease  upon  the  exposed  portion  of  the  tooth  in 
the  mouth,  I  can  see  no  other  correct  course  than  to  seek  for 
the  cause  of  malformation  in  the  beginning  of  the  formation  of 
cementum, — ^to  wit,  during  the  first  year  of  extra- uterine  life. 
Hyperostosis  of  this  kind  invades  the  roots  from  the  apex  to 
the  middle,  to  two-thirds  their  length,  sometimes  even  to  their 
necks.  The  enlargement  is  either  blending  with  the  crown, 
without  a  distinct  boundary  line,  or  there  is  a  more  or  less 
marked  bulging  of  the  augmented  tissue.  The  enlarged  por- 
tion is  either  in  a  more  or  less  horizontal  line  or  is  fluted,  with 


334 


THE  AX  ATOMY  AND  PATHOLOGY  OF  THE  TEETH. 


liere  and  there  irregular  prolongations  toward  the  crown.  In 
one  instance  I  have  seen  a  small  enamel-nodule  corresponding 
exact!}'"  to  the  summit  of  a  marked  conical  prolongation  of  the 
cementum.  Sometimes  the  bulging  of  the  cementum  reaches 
the  crown,  and  may  be  distinctly  seen  overlapping  the  enamel. 
Such  formations  are  usually  either  smooth  or  slightly  nodulated. 
Sometimes  they  are  corroded  as  if  by  inflammation  ;  and,  again, 
upon  a  comparatively  smooth  mass  there  may  be  found  bulging 
forth  an  irregular  nodule  of  circumscribed  osteoma,  evidently 
the  result  of  an  excessive  formative  pericementitis. 

"  In  one  of  my  specimens,  a  left  upper  second  molar,  there 
is  upon  the  anterior  surface  of  the  buccal  root  a  pit  two  and  a 
half  millimeters  in  diameter  and  one  millimeter  in  depth,  the 
base  of  the  pit  being  finely  corroded  and  nodular.  On  the 
same  surface  numerous  small  nodules  are  scattered  about.     On 


Fig.  189. 


•-^xy 


the  neck  the  hyperplastic  cementum  is  one  millimeter  in  thick- 
ness, and  terminates  all  around  it  in  a  nearly  abrupt  line.  (Fig. 
189,  a.) 

"  On  a  right  upper  second  molar  the  palatal  root  exhibits  at 
its  apex  a  cauliflower-like  excrescence,  upon  a  comparatively 
smooth  osteoma,  about  one  millimeter  in  thickness,  occupying 
the  upper  two-thirds  of  the  root.  The  excrescence  sends  a  deli- 
cate conical  offshoot  to  the  mass  which  cements  the  buccal  roots 
together.  The  posterior  portion  of  the  crown  of  this  tooth  has 
a  carious  canity  in  it  the  size  of  a  French  pea,  with  the  pulp- 
chamber  opened.     (Fig.  189,  b.) 

"  Roots  of  this  kind  look  very  clumsy  and  shortened,  for  the 
reason  that  at  the  place  of  their  union  the  hyperostosis  forms  a 
heavier  mass,  which  has  more  or  less  filled  the  space  between 
them;  still,  they  remain  separate  to  a  considerable  extent. 


HYPEROSTOSIS  OF  ROOTS  OF  TEETH. 


335 


"  III.  Diffused  Hyperostosis  with  Roots  United. — This  group 
mav  be  subdivided  as  follows  : 

"A.  Apices  free  and  straight ; 

"  B.  Apices  free  and  curved; 

"  C.  All  roots  united  their  entire  length. 

"  Teeth  of  the  group  A  are  characterized  l)v  an  osseous  out- 
growth of  cementum  accumulating  at  the  point  of  junction  of 
the  roots, — the  roots  themselves  being  either  slender  and  free 
from  osteoma  or  slightly  thickened.  An  upper  wisdom-tooth 
presenting  this  anomaly  has  five  roots,  three  of  which  are  nor- 
mal at  their  apices,  the  fourth  being  the  seat  of  a  ditiused  hyper- 
ostosis encircling  it,  and  the  fifth  root  being  rudimentary.  All, 
however,  are  united  into  a  common  mass  a  short  distance  from 
their  apices,  which  mass  gradually  blends  with  the  enamel. 
(Fig.  190,  a.) 


Fig.  190. 


Fig.  191. 


"  Teeth  of  the  group  B  exhibit  a  union  of  the  roots  with 
markedly  devious  but  slender  apices.  A  left  upper  second 
molar  of  my  collection  shows  this  evidently  rare  anomaly.  The 
palatal  root  is  slightly  devious,  with  an  apex  arising  from  the 
main  mass  of  the  root  at  a  right  angle.  The  buccal  root  (there 
is  but  one)  shows  two  curvatures,  both  at  right  angles.  The 
osteoma  is  only  moderately  large,  and  on  the  posterior  surface, 
at  the  point  of  junction  of  the  roots,  there  is  wedged  in  a  sessile 
oblong  nodule,  below  which  is  a  shallow  furrow,  indicating  the 
original  point  of  separation  of  the  two  roots.  The  crown  of 
this  tooth  is  not  decayed.     (Fig.  190,  b.). 

"  Teeth  of  the  group  C  are  rather  common.  In  third  molars 
or  wisdom-teeth,  of  both  the  upper  and  lower  jaws,  a  union  of 
the  roots  is  quite  generally  the  normal  condition.  Osteoma, 
when  found  upon  such  roots,  is   either  a  clumsy  nodular  mass 


336  THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

without  any  sign  of  a  previous  separation,  or  slight  furrows  may 
be  visible  indicative  of  such  separation  of  the  roots.  (Fig. 
190,  c.) 

"  Connected  with  a  lower  left  wisdom-tooth  in  my  collection 
there  is  a  history  that  I  will  give  in  abstract,  feeling  that  it  may 
be  of  interest  to  some  who  may  hear  or  read  it.  This  tooth 
exhibits  a  diffused  osteoma,  ridged  and  nodulated,  with  a  bent 
apex  toward  the  ramus.  It  was  extracted  from  the  mouth  of  a 
lady  some  years  since  by  my  friend,  Dr.  S.  A.  Main,  of  this  city, 
who  kindly  presented  it  to  me  with  the  following  history  :  For 
some  ten  years  this  lady  had  suffered  most  excruciatingly  from 
facial  neuralgia.  She  consulted  the  best  medical  talent  at  home 
without  obtaining  the  slightest  relief.  Finally,  some  three  years 
before  the  tooth  was  removed,  she  went  to  London,  where  it 
was  determined  by  the  surgeon  who  was  called  to  attend  her 
that,  in  order  to  afford  any  relief,  it  would  be  necessary  to  sever 
the  facial  nerve  upon  the  side  which  seemed  the  most  affected, 
which  operation  was  done, — with,  however,  only  temporary 
relief.  A\"ith  the  hope  that  the  slight  cessation  of  pain  would 
be  speedily  followed  by  permanent  cure,  she  went  to  Paris, 
anticipating  the  pleasure  of  a  comfortable  tour  of  the  Conti- 
nent. In  a  few  days  the  pain  returned  with  renewed  energy. 
In  Paris  she  consulted  a  surgeon,  who  decided  that  the  only 
chance  for  permanent  relief  was  to  have  the  facial  nerve  divided 
upon  the  other  side  of  the  face.  The  operation  was  performed 
with  no  better  results  than  from  the  first.  Finally  she  con- 
cluded to  return  to  her  home  in  ^ew  York,  there  to  spend  the 
few  days  (as  she  supposed)  which  she  had  to  live  as  comfortably 
as  possible.  Shortly  after  arriving  at  her  home  she  consulted 
her  dentist  (whom,  by  the  way,  she  had  never  thought  to  con- 
sult before  in  reference  to  her  neuralgia),  and  asked  him  to  look 
at  this  tooth,  saying  at  the  same  time  that  it  often  felt  quite  sore 
to  the  touch.  (Its  antagonist  had  been  taken  out  many  years 
before.)  After  examination,  she  was  advised  to  have  it  ex- 
tracted, which  was  done.  Immediately  upon  its  removal  the 
lady  realized  that  the  cause  of  her  long-continued,  fearfully  dis- 
tressing, and  very  expensive  neuralgia  had  been  found  at  last,  as 
time  proved. 

"IV.  Union  of  Two  Teeth  through  Hyperostosis. — Of  this 
rare  occurrence  of  the  osseous  union  of  teeth  I  have  some  eight 
fine  specimens.     The  subdivision  suggesting  itself  is  as  follows  : 


HYPEROSTOSIS  OF  ROOTS  OF  TEETH. 


337 


"  A.  Union  of  the  roots  at  their  apices  (Fig.  191,  a,  b); 

'•  B.  Union  of  the  roots  at  their  middle  (Fig.  192,  a,  b); 

"  C.  Complete  nnion  of  the  roots  (Fig.  192,  c). 

"  The  first  group  is  characterized  by  a  union  of  devious  roots 
of  neighboring  teeth.  As  both  of  my  specimens  show  a  partial 
carious  destruction  of  their  crowns,  the  idea  may  suggest  itself 
tliat,  owing  to  a  destruction  of  the  interveoing  alveolar  wall, 
and  owins:  to  o-ravitation,  the  roots  became  attached  to  each 
other  through  an  inflammatory  process.  At  the  same  time 
serious  objections  may  be  raised  against  such  a  view.  The  main 
objection  is  that  an  inflammation  of  the  pericementum  sufli- 
ciently  intense  to  destroy  the  alveolus  would  be  very  liable  to 
destro}'  the  pericementum  itself,  to  such  a  degree  as  to  render 
quite  impossible  the  secondary  new  ibrmation  of  cementum 
necessary  for  agglutination  of  the  neighboring  roots.  Should 
we  assume  that  the  septum  was  originally  absent,  the  only  way 


of  explaining  such  formations  is  to  suppose  that  at  least  one  of 
the  germs  of  the  coalesced  teeth  was  malposed  at  the  time  of 
the  embryonic  arrangement.  In  this  view,  it  will  be  observed, 
the  alveolar  septum  did  not  form  at  all,  and  at  the  time  of  de- 
velopment of  the  roots  the  mutual  pressure  was  sufficient  to 
cause  irritation  leading  to  a  new  formation.  I  conclude,  there- 
fore, that  the  carious  destruction  of  the  crowns  was  merely  a 
coincidence  rather  than  a  cause  (Fig.  191,  a).  The  roots  of  one 
tooth  are  mere  stumps  left  after  carious  destruction  of  the  crown 
and  a  portion  of  the  roots.  Here  the  hyperplastic  cementum 
of  the  stumps  is  jagged  and  nodular,  plainly  indicating  that  the 
already  formed  outgrowth  of  cementum  has  been  destroyed  by 
cementitis  in  rather  a  secondary  manner.     (Fig.  191,  6.) 

"  Group  B  shows  a  concretion  of  neighboring  roots  of  molars 
at  the  middle,  upon  one  side,  and  at  the  apices  upon  the  other. 
(Fig.  192,  a.)     One  of  the  crowns  is  slightly  afifected  by  caries, 

28 


338       THE  AIS^ ATOMY  AND  PATHOLOGY  OF  THE  TEETH. 

— ^by  no  means,  however,  to  sucli  a  degree  as  to  account  for 
agglutination  of  the  two  teeth,  the  enlarged  cementum  of  which 
is  mainly  smooth.  Fig.  192,  b,  represents  two  molars  grown 
together  nearly  the  entire  length  of  their  roots ;  both  teeth 
being  otherwise  sound.  One  of  them  shows  at  its  neck  an 
'  enamel-drop,'  which  feature  I  consider  a  further  proof  of 
embryonal  malformation  of  such  teetb.  Some  exostoses  from 
the  sockets  are  attached  to  the  roots,  which  fact,  in  mj^  judg- 
ment, proves  merely  a  secondary  hyperplastic  pericementitis. 

"  Group  C  is  represented  by  but  one  specimen, — that  of  an 
upper  cuspid  united  with  a  neighboring  lateral  incisor.  This 
seems  to  be  a  case  which  may  be  considered  an  exception  to  the 
rule, — viz,  that  only  bicuspids  and  molars  are  thus  affected.  In 
this  case  the  union  is  perfect  the  entire  length  of  the  roots,  and 
only  shallow  furrows  on  the  outer  and  inner  surfaces,  reaching 
nearly  to  a  common  apex,  indicate  the  previous  separation. 
The  apex  presents  but  one  large  common  foramen.  At  the 
necks  of  both  teeth  there  is  shallow  carious  destruction, — not, 
however,  exposing  the  pulp-chambers.  All  these  features  fur- 
nish us  proof  of  a  foetal  malformation. 

"  For  the  purpose  of  examining  this  disease  microscopically, 
I  have  ground  quite  a  large  number  of  specimens  from  teeth 
which  at  the  time  of  extraction  were  immediately  placed  in 
dilute  alcohol,  in  order  to  keep  them  constantly  wet,  and  to  pre- 
serve their  soft  parts.  During  the  process  of  grinding  they 
were  also  kept  under  water.  All  specimens  showed  in  common 
a  number  of  features  which  are  represented  with  a  compara- 
tively low  power  in  Fig.  193.  Those  to  which  1  wish  to  call 
attention  are  as  follows  : 

"  The  dentine  in  some  specimens, perhaps  in, several  localities 
in  the  same  specimen,  was  found  in  a  normal  condition;  and  in 
others  it  exhibited  the  so-called  interglobular  spaces,  greatly 
varying  in  size  and  number,  indicative  of  an  incomplete  calcifi- 
cation. 

"  In  some  specimens  the  dentinal  canaliculi  of  the  root  were 
arranged  in  bundles,  between  which  were  found  areas  scantily 
provided  with  canaliculi  or  altogether  destitute  of  them.  In 
these  areas  are  often  seen  small  interglobular  spaces,  sometimes 
in  direct  union  with  a  few  canaliculi. 

"  The  interzonal  layer  between  dentine  and  cementum  invari- 
ably exhibited  formations  known  under  the  name  of  osteo-den- 


HYPEROSTOSIS  OF  ROOTS  OF  TEETH. 


339 


tine,  or  globular  dentine,  either  as  the  result  of  '  eburnitis '  or 
of  incomplete  calcification .  It  is  a  condition  kindred  to  that 
which  characterizes  the  interglobular  spaces  of  Czermak.  Such 
formations,  as  a  rule,  extend  into  the  neck  of  a  tooth, — where, 
however,  they  are  more  scanty  than  on  the  roots.  A  striking 
feature  is  their  entire  absence  at  the  point  of  junction  of  the 
roots.  Here  the  cementum  is  found  in  contact  with  an  irregular 
formation  of  dentine  (vaso-dentine),  which  will  be  described 
farther  on.  Wedl  seems  to  have  been  the  first  to  illustrate  this 
formation, — without,  however,  making  an  allusion  to  it  in  his 
text. 

Fig.  193. 


Iillliliiili& 


Hyperplastic  Cemextuji  slightly  bulgixg  tottahd  the  Neck  of  the  Tooth  (Upper 
Bicuspid).    Longitudixal  Section. 

Z),  dentine  :  iV.  neck:  P,  pericementum;  0,  globular  or  osteo-dentine  ;  G^,  granular  layer; 
H.  hyperplastic  cementum  irregularly  lamellated,  with  irregularly-distributed  cement-cor- 
puscles ;  M,  medullary  canal.    Magnified  150  diameters. 

"  IsText  to  the  layer  of  osteo-dentine  invariably  a  layer  is  found 
which,  under  lower  powers  of  the  microscope,  looks  coarsely 
granular,  and  which  in  consequence  I  propose  to  call  the  granu- 
lar layer.  It  is  destitute  of  cement-corpuscles,  and,  as  a  rule,  is 
the  only  layer  comprising  the  cementum  of  the  neck  of  the  tooth, 
whenever  this  gradually  slopes  from  the  hyperplastic  cementum 
to  the  enamel,  ISText  follows  the  enlarged  cementum  itself, 
xisually  characterized  by  a  large  number  of  irregular  lamellae 


340  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

more  or  less  concentric  to  the  axis  of  the  root.  Some  areas  may 
be  found  destitute  of  lamellae ;  others  very  richly  supplied  with 
them.  At  the  border  of  the  cementum  toward  the  crown, 
where  the  former  often  bulges  to  a  considerable  extent,  tbe 
lamellse  are  found  parallel  with  the  outer  periphery  of  the  ce- 
mentum inosculating  with  the  granular  layer  at  obtuse  angles. 

"In  thelamellated  basis-substance  are  found  scattered  cement- 
corpuscles.  The  most  striking  features  of  these  corpuscles  are  as 
follows :  First,  they  are  far  more  irregularly  distributed  in  the 
basis-substance  than  in  normal  cementum.  In  some  portions  of 
the  hyperplastic  cementum  such  corpuscles  are  comparatively 
few,  whether  the  lamellse  be  plaiidy  marked  or  not;  in  other 
portions  they  are  arranged  in  groups  or  clusters  apparently  with- 
out any  regularity.  Second,  the  cement-corpuscles,  as  a  rule, 
are  smallest  near  the  granular  layer,  and  largest  toward  the 
periphery;  at  the  latter  boundary  their  oifshoots  are  much  wider, 
and  more  irregular,  often  piercing  the  lamellse  rectangularly. 
i^o  constant  relation  between  lamellfe  and  cement-corpuscles  is 
to  be  found.  Third,  occasionally  the  cement-corpuscles  are  to  be 
seen  in  large  numbers  clustered  together  in  longitudinal  groups. 
This  is  probably  caused  by  the  previous  presence  of  medullary 
canals,  the  tissue  of  which,  at  a  comparatively  late  period,  has 
given  rise  to  a  large  number  of  cement-corpuscles,  and  a  com- 
paratively small  amount  of  basis-substance  between  them. 

"  The  hyperplastic  cementum  is  often  traversed  by  medullary 
canals  carrying  central  blood-vessels.  These  are  most  numerous 
at  or  near  the  point  of  junction  of  the  roots,  where,  as  first  de- 
scribed by  Tomes,  even  normal  cementum  may  sometimes  con- 
tain medullary  canals.  The  vessels  of  these  medullary  canals,- 
also  first  described  by  Tomes,  with  whom  I  am  pleased  to  agree, 
are  in  direct  connection,  and  anastomose  with  the  blood-vessels- 
of  the  pericementum.  In  one  of  my  specimens  the  cementum 
of  the  ne^k  exhibits  peculiar  features.  Instead  of  the  coarsely- 
granular  layer  usually  present,  and  previously  alluded  to,  there 
is  a  zone  traversed  nearly  at  right  angles  by  bundles  of  canali- 
culi,  very  broad  and  in  no  connection  whatever  with  cement- 
corpuscles.  Aliove  this  zone  lies  the  ordinary  granular  zone, 
bordered  toward  the  dentine  by  a  thin  layer  of  globular  den- 
tine; then  follows  the  finely-granular  laj-er  of  the  dentine  itself, 
with  very  few  or  no  canaliculi,  and  at  last  we  come  to  the  canali- 
culated  dentine  of  normal  development.     (Fig.  194.) 


HYPEROSTOSIS  OF  ROOTS  OF  TEETH. 


341 


"  High  amplifications  plainly  reveal  the  structure  of  the  inter- 
■zonal  layer  between  dentine  and  hyperplastic  cementum.  The 
dentine  often  shows  interglobular  spaces,  which  as  a  rule  are 
filled  with  granular  protoplasm,  and  serve  as  the  termination  of 
some  dentinal  canaliculi ;  especially  for  their  tenants,  the  fibers 
of  living  matter.  The  interglobular  spaces  nearest  to  the 
cementum  sometimes  directly  inosculate  with  the  interstices 
between  the  globular  masses  of  calcified  basis-substance,  consti- 
tuting the  tissue  termed  osteo-dentine  or  globular  dentine.    The 

Fig.   194. 


D 


wmmmmmmm 


r-/:^ 


J-j-".! 


o  %': 


|feiifS^^#t| 


iV 


Hypeeplastic  Cemextum  of  thk  Neck  of  a  Molak.     Longitudinal  Section. 
N,  zone  of  coarsely-granulated  cementum,  traversed  by  bundles   of  coarse  canaliculi:  G. 
granular  zone,  destitute  of  canaliculi ;  O,  zone  of  globular  dentine  ;  D,  dentine  with  canaliculi 
stopped  short  of  the  cementum.    Magnified  500  diameters. 

globules  themselves  vary  greatly  in  size.  They  usually,  how- 
ever, correspond  with  the  bulk  of  one  or  a  limited  number  of 
medullary  corpuscles  present  before  their  transformation  into 
basis-substance.  The  interstices  between  the  globules  also  vary 
in  size,  and  send  oifshoots  into  the  larger  globules,  subdividing 
them  into  incomplete  smaller  ones.  All  of  them  contain  granu- 
lar protoplasm.  In  the  granular  zone  following  the  layer  of 
osteo-dentine  we  sometimes  meet  with  very  large  and  irregular 
interglobular  spaces,  apparently  in  no  direct  connection  with 


342 


THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 


the  oifshoots  of  cement-corpuscles.  In  several  specimens  I  have 
seen  arising  from  the  cement-corpuscles  very  long  and  slightly 
wavy  offshoots,  which,  owing  to  their  parallel  course,  bear  a 
close  resemblance  to  dentinal  canaliculi.     Formations  of  this 


Pig.   195. 


Inteezoxal  Layer  between  Dentixe  and  Hyperplastic  Cementum  of  a  Molar. 
Longitudinal  Section. 

-D,  dentine  with  small  interglobular  spaces:  0,  osteo-dentine,  above  which,  in  the  granular- 
layer  G,  there  is  a  large  irregular  interglobular  space  ;  C,  C,  cement-corpuscles  with  long  panillel 
offshoots.    Magnified  600  diameters. 

kind  occur  only  in  those  layers  of  hyperplastic  cementum  near- 
est the  dentine,  and  always  lose  themselves  in  the  granular  layer- 
above  the  osteo-dentine  without  directly  communicating  with 
the    dentinal  canaliculi   proper.      (Fig.    195.)     The    medullary 


HYPEROSTOSIS    OF    ROOTS    OF    TEETH, 


343 


canals  traversiiisf  the  enlaro-ed  eementum  either  contain  medul- 
lary  corpuscles  and  capillary  blood-vessels,  or  the}'  are  filled  with 
highly-refracting  grannies  and  globules  of  lime-salts,  as  described 
by  Wedl.  Should  their  canals  become  obliterated,  they  give 
rise  to  groups  of  cement-corpuscles  between  a  scantily-calcified 
basis-substance. 

"  At  the  point  of  junction  of  the  enlarged  roots  in  several  of 
my  specimens  I  have  met  with  a  peculiar  formation  of  dentine, 
and  as  it  contains  a  large  number  of  vascular  canals,  I  propose 
to  term  it  vaso-dentiue.     To  the  naked  eye,  in  the  prepared 


Fro.   196. 


^^. 


M      '^l! 


V-D 


.-  ml 


Vaso-Dentine  from  the  Junction  op  the  Enlarged  Roots  of  an  Upper  Molar. 
Longitudinal  Section. 

B,  primary  dentine ;  Y-B,  vaso-dentine  traversed  by  medullary  canals  in  a  plexiform 
arrangement, — the  canals  contain  either  blood-vessels  or  glistening  depositions  of  lime-salts  ; 
B,  basis-substance  of  dentine  scantily  provided  with  extremely  delicate  canaliculi,  and  in 
some  places  fan-  and  fountain-shaped  figures  of  dentinal  canaliculi  discernible  ;  C,  hyperplas- 
tic eementum  lamellated,  and  containing  a  medullary  canal.    Magnified  50  diameters. 


specimen,  a  high  degree  of  transparency  in  the  vaso-dentine  at 
once  distinguishes  it  from  the  neighboring  opaque  portions  of 
normal  dentine,  and  from  eementum.  Low  powers  of  the 
microscope  reveal  in  this  dentine  a  varying  number  of  medul- 
lary canals,  either  in  a  parallel  or  plexiform  arrangement.  The 
canaliculi  contain  medullary  tissue  and  capillary  blood-vessels, 
one  or  two  in  each  canal.  Sometimes  glistening  granules  ot 
lime-salts  are  found,  more  especially  in  dilated  portions  of  the 


344  THE    ANATOMY    A1>!D    PATHOLOGY    OF    THE    TEETH. 

canals.  Offshoots  of  sucli  canals  may  inosculate  with  very  nar- 
row canals  containing  granular  protoplasm  only.  The  surround- 
ing basis-substance  is  scantily  supplied  with  extremely  fine  caua- 
liculi,  running,  without  any  apparent  regularity,  in  fan-shaped 
groups,  or  parallel  with  the  medullary  canals,  or  in  the  shape  of 
a  fountain,  encircling  the  canals  in  the  most  beautiful  and 
striking  figures.  Some  portions  of  the  basis-substance  may 
look  granular  and  devoid  of  canaliculi ;  others  (and  these 
formed  a  vast  majority)  are  apparently  homogeneous,  and  scan- 
tily supplied  with  extremely  minute  canaliculi.  The  ceraentum 
is  directly  on  the  border  of  the  vaso-dentine,  without  any  inter- 
vening layer  of  granular  dentine,  and  the  cement-corpuscles 
nearest  to  the  dentine  are  in  direct  connection  with  the  dentinal 
canaliculi  themselves.  (Fig.  196.)  Higher  powers  of  the  mi- 
croscope brought  to  bear  upon  the  vaso-dentine  plainly  show 
the  medullary  contents  of  the  medullary  canals,  in  which  may 
also  be  seen  one  or  two  capillary  blood-vessels.  Both  the 
canals  and  blood-vessels  produce  loops,  as  is  indicated  by  their 
abrupt  terminations  in  vertical  sections,  and  are  unquestionably 
in  communication  with  the  blood-vessels  of  the  pericementum 
(Tomes).  A  peculiar  feature  of  the  vaso-dentine  is  that  por- 
tions freely  supplied  with  vascular  canals  contain  a  considerably 
laro;er  number  of  dentinal  canaliculi  than  those  devoid  of  vas- 
cular  canals, 

"  The  canaliculi  in  the  neighborhood  of  the  vascular  canals 
are  very  irregular  in  their  course,  as  before  stated,  and  often 
loop-shaped,  starting  from  and  inosculating  with  the  same  vas- 
cular canal.  Again,  we  find  them  starting  from  club-,  pear-, 
spindle-,  and  irregular-shaped  spaces,  containing  medullary  cor- 
puscles, or  granular  protoplasm,  but  no  blood-vessels.  (Fig. 
197.)  I  would  mention  that  in  all  my  specimens,  as  an  addi- 
tional feature  of  hyperostosis  of  the  roots,  the  pulp-chamber 
and  often  the  canals  appear  considerably^  narrowed  by  heavy 
formations  of  secondary  dentine.  Besides,  the  pulp-tissue  was 
found  to  contain  formations  of  secondary  dentine  known  as 
pulp-stones,  or  to  be  crowded  with  globular  calcareous  deposi- 
tions of  no  definite  structure.  In  the  majority  of  the  teeth  the 
enamel  also  was  imperfectly  formed,  it  generally  presenting  a 
highly -pigmented  and  imperfectly-calcified  condition,  with 
enamel-rods  very  irregular  and  curly. 

"  A  striking  feature  in  all  microscopical  specimens  of  hyper- 


HYPEROSTOSIS    OF    ROOTS    OF    TEETH. 


345 


plastic  cementum  is  tlie  great  number  and  large  size  of  the  off- 
shoots of  the  cement-corpuscles,  the  canaliculi,  previously  so 
called.     The  reason  for  this  seems  to  be  that  both  the  corpuscles 


Fig.  197. 


V-D 


B-n 


Vaso-Dentine  from  the  Point  of  Junction  op  the  Enlarged  Root  of  an  Upper 
Bicuspid.    Longitudinal  Section. 

V-D,  a  portion  of  vaso-dentine  with  three  parallel  vascular  canals,  and  very  irregular,  often 
looped,  canaliculi,  some  starting  from  the  vascular  canals  and  others  from  smaller  medullary 
spaces ;  B-D,  dentine  of  great  transparency,  with  scanty  canaliculi.  The  boundary  line  be- 
tween the  two  portions  is  abrupt,  with  numerous  bay-like  excavations.  Magnified  500  diam- 
eters. 

(lacunae)  and  their  coarser  offshoots  (canaliculi)  are  filled  with 
air,  or  dirt  from  the  grinding,  which  causes  them  to  look  black. 


346 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


If,  however,  we  place  a  carefully  but  not  completely  decalcified 
portion  of  this  tissue,  mounted  in  glycerin,  under  a  very  high 
power,  we  are  struck  with  its  beautiful  and  graceful  appearance. 
It  is  identical  in  structure  with  that  of  normal  cementum.  The 
basis-substance  forms  cavities  that  contain  nucleated  protoplas- 
mic bodies,  the  cement-corpuscles  proper,  of  a  markedly  reticu- 
lated structure. 

"Between  the  periphery  of  the  cement-corpuscles  and  that 
of  the  lacuna  there  is  a  narrow  light  rim,  obviously  correspond- 
ing to  a  space  that  serves  for  the  circulation  of  the  nutritive 
liquids.     The  lacuna  at  its  periphery  is  interrupted  by  numerous 


Htpeeplastic  Cementum  of  an  Upper  Molar.     Cross  Section. 
Magnified  1500  diameters. 


offshoots,  wider  and  more  irregular  than  those  of  normal  ce- 
mentum. These  canaliculi  form  an  extremely  delicate  reticulum 
throughout  the  basis-substance,  interconnecting  the  neighboring 
lacunae  (indeed,  all  lacunae)  of  the  cementum. 

"  Starting  from  the  periphery  of  the  cement-corpuscles,  coni- 
cal offshoots  run  into  the  canaliculi ;  the  broader,  of  course,  the 
wider  the  canaliculus.  The  coarsest  otfshoots  still  exhibit  a 
reticular  structure ;  whereas  the  finest  are  merely  beaded  threads 
occupying  the  middle  of  the  canaHculi.  Thus  it  will  be  seen 
that  all  canaliculi  hold  filaments  of  living  matter  in  a  cobweb 


HYPEROSTOSIS  OF  ROOTS  OF  TEETH.  347 

arrangement,  and  thus  it  becomes  plain  tliat  hyperplastic  as  well 
as  normal  cementum  is  a  living  tissue  throughout.  The  reticular 
structure  of  the  living  matter  in  the  corpuscle  itself  is  plainly 
visible.  The  inert  basis-substance,  infiltrated  at  the  same  time 
v\dth  lime-salts,  is  located  in  the  meshes  of  the  reticulum  of  the 
canaliculi,  and  between  the  basis-substance  and  filaments  of  liv- 
ing matter  a  slow  circulation  is  going  on,  the  liquid  carrying 
nourishment  and  taking  away  the  effete  material.  (Fig.  198.) 
Thus  it  is  that  pathological  changes  of  a  pathological  tissue 
become  intelligible,  and  cementitis  of  hyperplastic  cementum, 
as  described  and  illustrated,  by  Wedl,  under  the  terra  '  perforating 
resorption,'  is  understood. 

"  Macroscopically  I  have  already  described  this  condition. 
Under  the  microscope  it  is  characterized  by  the  presence  of 
cavities  filled  with  medullary  corpuscles,  or  multinuclear  proto- 
plasmic masses,  and  bounded  toward  the  unchanged  cementum 
with  numerous  bay-like  excavations.  The  destruction  may 
involve  superficial  portions  of  the  tumor  only,  or  the  entire 
mass  down  to  the  dentine.  As  there  is  little  tendency  to  suppura- 
tive pericementitis,  the  termination  of  the  inflammatory  process 
undoubtedly  results  often  in  a  re-formation  of  cementum,  the 
same  as  takes  place  duiing  the  process  of  absorption  of  the 
roots  of  temporary  teeth.  Under  these  circumstances  the  bay- 
like excavations  are  refilled  with  bone-tissue,  and  the  bays  are 
recognizable  by  sharply-defined  lines  corresponding  to  the  terri- 
tories of  the  cement-corpuscles.  Some  of  m}^  specimens  ex- 
hibit bay-like  excavations  directly  separating  the  cementum 
from  the  dentine,  and  the  bays  filled  with  bone-tissue  crowded 
with  cement-corpuscles.  In  other  specimens  certain  portions  of 
the  hyperplastic  cementum  show  distinct  circular,  semicircular, 
or  crescentic  lines  corresponding  to  the  territory  of  one  or  more 
cement-corpuscles." 


348  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

CHAPTER  XXXI. 

INFLAMMATION.* 

"  It  is  the  gift  of  genius  to  foresee  discoveries  even  for  cen- 
turies. Such  a  genius  was  John  Hunter,  of  London,  who 
toward  the  end  of  the  last  century,  merely  upon  the  ground  of 
speculation  and  ratiocination,  made  the  assertion  that  inflam- 
.mation  is  none  other  than  a  return  of  the  tissues  to  embryonic 
condition.  And  our  present  knowledge  of  the  process  of  in- 
flammation and  suppuration  is  a  strong  proof,  supported  by 
careful  researches  of  good  pathologists  of  Germany  and  Eng- 
land, that  Hunter's  theory  was  the  correct  one. 

"  Since  microscopy  became  a  science  (a  period  covered  by 
half  a  century)  the  views  concerning  the  intimate  nature  of  the 
inflammatory  process  have  been  greatly  at  variance.  These 
views  largely  depend  upon  the  general  ground  taken  by  pathol- 
ogists in  reference  to  the  pathological  processes  at  large.  "We 
have  three  marked  phases  in  the  development  of  pathology 
within  the  lastflfty  years.  The  first  is  the  standard  of  humoral 
pathology  promulgated  by  the  late  C.  Rokitansky,  of  Vienna. 
The  second  is  the  phase  of  cellular  pathology  established  mainly 
by  R.  Virchow,  of  Berlin.  The  third  phase,  still  in  vogue  with 
many  pathologists,  is  the  doctrine  of  emigration  of  colorless 
blood-corpuscles  or  leucocytes,  as  propounded  by  the  late  I. 
Colin heim,  of  Leipsic. 

"  During  the  past  five  years  bacteriology  has  held  sway  of 
the  minds  of  the  majority  of  the  pathologists,  proving  what  was 
just  stated.  To-day  no  one  will  be  rash  enough  to  neglect  the 
influence  of  bacteria  in  producing  suppuration.  And  have  we 
not  learned  through  excellent  observers  that  it  is  not  the  micro- 
organisms themselves,  but  rather  their  chemical  products,  the 
ptomaines,  that  play  the  important  role  in  the  causation  of  sup- 
puration and  possibly  of  inflammation  ?  I  here  allude  to  the 
researches  of  Leber,  of  Gottingen,  who  maintains  that  it  is  a 
ptomaine,  called  by  him  j^hlogestein,  that  stands  in  causal  relation 
to  inflammation. 

"  The  task  I  have  undertaken  is  to  review  the  theories  held 

*  Much  of  this  chapter  is  based  upon  the  investigations  of  Wm.  H.  Atkinson  : 
"The  Origin  of  Pus,"  Journal  of  the  American  Medical  Association,  1889. 


INFLAMMATION.  349 

in  the  last  fifty  years,  closing  the  historical  remarks  with  a 
description  of  what  I  consider  to  he  the  truth  to-day.  The 
review  of  such  a  history  is  instructive  in  many  respects.  It 
teaches  us  that  no  one,  he  he  of  the  most  gifted  talent,  is  ahle 
to  emancipate  himself  from  preconceived  ideas  and  accepted 
notions.  It  furthermore  teaches  us  that  we  are  the  subjects  of 
general  theories  extant  at  the  time  in  which  Ave  make  our 
investigations.  It  teaches  the  great  lesson  of  modesty  and 
humility.  If  a  man  of  my  age  must  confess  in  the  seventh 
decade  of  his  career  that  he  has  been  misled  iu  his  younger 
days  by  books  and  teachers  and  must  try  hard  to  unlearn  what 
he  thought  he  knew  before,  it  is  certainly  testimony  of  human 
frailty,  and  goes  far  to  prove  that  we  are  obliged  to  consider 
the  truth  to  l)C  truth  only  jJro  tempore^ — viz,  so  long  as  we  do  not 
know  better. 

"  In  the  fifth  decade  of  our  century  humoral  pathology  was 
thought  to  hold  the  full  truth  in  the  explanation  of  inflamma- 
tion. The  older  of  us  will  remember  what  facts  the  humoral 
pathology  was  based  upon.  The  web  of  the  foot  of  a  living 
frog  was  expanded  over  a  cork  ring  and  the  web  touched  with 
an  irritating  agent,  such  as  a  droplet  of  ammonia,  an  acid,  or 
with  a  pointed,  red-hot  iron,  and  the  subsequent  changes 
observed  under  the  microscope  with  the  comparatively  low 
powers  at  the  disposal  of  investigators  of  the  time.  They  saw 
around  the  irritated  portion  of  the  web  an  undulation  of  the 
currents  of  the  blood  within  the  vessels,  shortly  afterward  a 
slacking  of  the  current,  and  still  later  a  standstill  of  the  stream. 
The  last  phenomenon  they  called  '  stasis,'  and  this  stasis  was 
thought  to  be  the  essential  feature  of  the  inflammatory  process. 
Many  and  animated  controversies  arose  over  the  question,  What 
is  the  stasis  due  to?  Most  observers  agreed  that  a  paralysis  of 
the  capillary  blood-vessels,  after  a  few  preceding  contractions, 
was  to  be  considered  the  cause  of  stagnation.  At  the  same 
time  an  inundation  was  seen  to  take  place  in  the  aft'ected  tissues 
with  a  liquid  which  of  necessity  must  have  come  from  the 
general  blood-column,  and  was  termed  '  exudate.'  According 
to  the  nature  of  the  exudate  difierent  varieties  of  inflammation 
were  set  up,  such  as  the  '  serous,'  the  '  fibrinous,'  the  '  albumin- 
ous,' and  should  blood  have  been  admixed  with  the  exudate,  the 
'  hfemorrhagic'  Corpuscular  elements  seen  in  the  affected  terri- 
tories and  apparently  suspended  in  the  exudate  were  thought  to 


350  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

have  originated  from  tlie  exudate  itself;  therefore  the  pas-cor- 
puseles  woukl  have  originated  from  the  exudate,  the  latter  from 
the  hlood,  hence  the  definition  of  pus, '  dead  blood.'  'No  stress 
was  laid  upon  the  structural  changes  of  the  affected  tissue  itself, 
except  so  far  as  the  exudate  saturating  this  tissue  was  concerned. 
The  ultimate  cause  of  inflammation  and  suppuration  was  sought 
in  chemical  mixtures  of  the  blood,  termed  clj^scrasia,  which 
means  bad  mixture  of  the  blood.  If  a  person  became  affected 
with  lobar  pneumonia  the  cause  surely  was  surplus  of  fibrin  in 
the  blood,  or  fibrinous  dyscrasia.  If  a  person  produced  a  num- 
ber of  abscesses  in  his  organism,  the  cause  was  denominated 
purulent  dyscrasia.  All  diseases  were,  in  this  dyscrasic  view, 
essentially  diseases  of  the  blood.  The  blood  in  its  mixture 
caused  the  diseases  simply  by  being  overloaded  with  obnoxious 
or  effete  material. 

"  The  man  who  dug  the  grave  of  humoral  pathology  was 
Virchow,  in  the  beginning  of  the  sixth  decade  of  the  present 
century.  To  him  the  phenomena  of  alterations  in  the  circula- 
tion of  the  blood  were  of  secondary  importance.  The  stasis 
he  would  not  admit  as  a  cardinal  symptom  of  inflammation,  for 
it  would  mean  rather  death  of  the  tissue,  gangrene  or  necrosis. 
The  exudate  also  plaj^ed  but  a  secondary  role,  serving  only  as 
a  pabulum  to  the  living  corpuscular  elements  of  the  tissues,  the 
so-called  cells.  Inflammation  was,  in  Yirchow's  opinion,  a 
structural  change  of  the  affected  tissue,  mainly  morphological 
changes  of  the  cells  themselves.  The  cells  being  the  seats  of 
life,  would  attract  and,  as  it  were,  imbibe  the  exudate,  swell  up, 
divide  and  come  to  a  state  of  proliferation,  in  which  a  number 
of  cells  would  arise  from  an  original  single  cell,  and  the  large 
number  of  newly-formed  cells  would  replace  the  intercellular 
substance  lost  by  liquefaction.  A  formation  of  cells  out  of  a 
previous  liquid  or  semi-solid  exudate  was  declared  to  be  impos- 
sible, since  all  newly  formed  cells  must  have  arisen  from  pre- 
existing cells.  Dyscrasias  Avere  done  away  with.  The  main 
causes  of  inflammation  were  peculiarities  of  the  tissue  itself, 
and  a  certain  weakness  of  the  tissue  was  proposed  to  explain 
the  predisposition  to  inflammatory  processes.  The  word  sug- 
gested for  this  supposed  local  weakness  of  the  tissue  was 
^  diathesis.'  If  a  man  suffered  from  articular  rheumatism,  the 
cause  was  said  to  be  '  rheumatic  diathesis.'  Tuberculous  persons 
were  predisposed  to  cheesy  degeneration  simply  because  they 


INFLAMMATION. 


351 


^vere  afflicted  with  tuberculous  cliatliesis.  In  the  same  sense 
hemorrhagic  and  purulent  diatheses  were  spoken  of.  The  pus- 
corpuscles  were  without  exception  an  offspring  of  the  previous 
cells  of  the  tissue,  and  in  this  sense  pus  was  considered  dead 
tissue.     Cellular  pathology  has  made  a  very  strong  impression 

Fig.  199. 


Diagram  of  the  Inflammatory  Chaxgf.s  of  Coxxectiye  Tissue.    Ckll-Prolifera- 
tiox  according  tu  r.  vlrcho^  (1852). 

A,  inflammatory  changes  of  reticular  cartilage.— a,  division  of  the  nucleus  of  the  cartilage- 
cell  ;  6,  division  of  the  cell  into  a  number  of  cells  ;  e,  proliferation  of  cells,— the  intercellular 
substance  gradually  liquefied.  B,  inflammatory  changes  of  fibrous  connective  tissue. — a,  divi- 
sion of  the  connective-tissue  cell ;  h,  further  advanced  division  of  the  connective-tissue  cell ;  c, 
high  degree  of  division  and  proliferation,— the  fibrous  intercellular  substance  gradually  lique- 
fied. 


on  the  minds  of  observers.  Even  the  stalwart  humoral  pathol- 
ogist Eokitansky  yielded  to  the  novel  views,  and  accepted  the 
doctrine  that  no  cell  will  grow  in  an  exudate  unless  previous 
cells  be  there.  Cellular  pathology  even  in  our  day  governs  the 
minds  of  most  pathologists  over  the  civilized  world.    Prolifera- 


352  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

tion  of  the  cells  accounts  for  all  tissue-changes,  either  newly 
formative,  the  so-called  hyperplasia,  or  destructive,  that  is,  sup- 
puration. Proliferated  cells  being  present  in  either  of  these 
instances,  cellular  pathoh^gy  is  at  a  loss  to  explain  why  a  certain 
tissue,  owing  to  proliferation  of  its  cells,  becomes  augmented 
and  hyperplastic  in  one  instance  and  is  destroyed  by  suppuraiion 
in  the  other.  Still,  in  spite  of  all  weaknesses  of  this  doctrine, 
we  must  consider  it  an  advance  in  comparison  with  the  teat-h- 
ings  of  humoral  pathology.  The  cell  being  supposed  to  be  the 
only  center  of  life,  inflammation  and  suppuration  were  for  the 
tirst  time  considered  as  the  phenomena  of  life,  and  the  idea 
began  to  dawn  in  the  minds  of  pathologists  that  inflammation 
and  suppuration  were  morbid  processes  occurring  in  tissue- 
elements  endowed  with  life,  the  so-called  cells.  (See  Fig. 
199.) 

"  The  third  period  arose  in  the  middle  of  the  seventh  decade 
of  our  century,  when  Cohnheim  observed  a  migration  of  color- 
less blood-corpuscles  through  the  walls  of  the  capillaries  and 
small  veins  of  an  exposed  and  expanded  meseutery  of  a  frog. 
Several  years  before  S.  Strieker,  in  Vienna,  observed  the  red 
corpuscles  pass  through  the  walls  of  the  capillaries  of  the  nicti- 
tant  membranes  of  the  live  frog,  so-called  diapedesis.  Even  in 
1848  the  emigration  of  leucocytes  had  been  seen  in  England  by 
"Walker  and  Wallace.  The  facility  with  which  the  emigration 
of  leucocytes  could  be  seen  under  the  microscope  has  induced 
many  German  pathologists  to  accept  the  view  of  Cohnhtim, 
that  inflammation  and  suppuration  are  but  an  emigration  of 
colorless  blood-corpuscles.  These  accumulating  in  a  tissue 
whose  cells  would  remain  inert  and  whose  intercellular  sub- 
stance would  become  liquefied  and  destroyed,  furnish  a  repre- 
sentation of  both  inflamn}ation  and  suppuration.  With  this 
view  there  was  nothing  alive  in  the  body  but  the  leucocytes. 
At  first  Cohnheim  denied  the  participation  of  the  so-called 
stable  cells  in  the  process  of  inflammation,  but  later  he  admitted 
that  in  reparative  inflammation  the  tissue-cells  do  proliferate 
and  furnh-h  their  share  for  the  benefit  of  newly-forming  tissue, 
exactly  in  the  sense  of  cellular  pathology.  That  pus-corpuscles 
should  be  emigrated  colorless  blood-corpuscles  was  intelligible, 
as  isolated  corpuscles  were  nearly  identical  in  appearance.  How 
new  tissue  could  form  from  leucocytes  remained  a  deeply- 
shrouded  mystery,  as  no   observation  has  as  yet  proved  that 


INFLAMMATION.  353 

through  coalescence  of  leucocytes  new  protoplasmic  masses  and 
new  tissues  can  arise.     The  observation  of  Ziegler,  of  Tiibingen, 
that  multinuclear  bodies,  so-called  giant-cells,  are  ^dsible  between 
thin  glass  plates  introduced  under  the  skin  of  an  animal,  lacks 
the  proof  that  such  giant-cells  arose  by  coalescence  of  leuco- 
cytes.    On  the  contrary,  later  observations  made  especially  upon 
deciduous,  replanted,  and  implanted  teeth,  go  far  in  proving  the 
giant-cells  to  be  an  offspring  of  the  myxomatous  granulation- 
tissue,  sprouting  in  all  directions,  filling  the  bay-like  excavations 
on  the  deciduous  and  other  teeth  and  carrying  blood-vessels  into 
places  where  there  had  been  none  before,  leading  to  the  vascular- 
ization of  a  new  tissue, — seen,  for  instance,  in  sponge-grafting. 
"  S.  Strieker  immediately  sought  to  overthrow  the  teachings 
of  Cohnheim.     In  his  investigations  he  used  almost  exclusively 
the  cornea  (chiefly  of  frogs,  cats,  and  rabbits),  in  which  he  in- 
duced inflammation  by  introducing  a  thread.     The   changes 
were  faithfully  watched  up  to  the  formation  of  abscess  around 
the  foreign  body.     The  observations  enabled  him  to  prove  the 
established  views  of  cellular  pathology  to  be  correct, — namely, 
that  these  so-called  cells  divide  and  subdi^dde,  but  also  that  the 
coarser  ofi'shoots  of  the  cornea-corpuscles  split  up,  and  by  divi- 
sion produce  new  corpuscular  elements.     Strieker  also  held,  up 
to  1874  (Ashhurst's  International   Surgical  Cyclopsedia),  that 
pus-corpuscles  were  products  of  proliferation  of  the  cornea- 
corpuscles  and  their  coarser  offshoots.    Unfortunately,  he  called 
all  the  products  of  cells  originating  from  proliferation  of  pre- 
vious  cells  pus-corpuscles.     Indeed,  it  was  impossible  to  dis- 
criminate between  inflammatory  corpuscles  and  pus-corpuscles, 
since  all  of  these    appeared  isolated   under   the   microscope. 
Clinically  it  is  well  established  that  every  inflammation  does 
not  terminate  in  suppuration.     Particularly  do  we  know  of  a 
termination  which  instead  of  causing  destruction  of  an  affected 
tissue,  as  suppuration  does,  brings  about  a  new  formation,  an 
increase  of  the  bulk  of  the  tissue, — the  so-called  hyi^erplasia. 
How  shall  we  explain  such  marked  differences  by  the  theory  of 
cellular  pathology,  which  claims  that  all  corpuscular  elements 
are  isolated  from  the  start?     However,  since  1880  Strieker  has 
been  a  convert  to  the  views  of  C.  Heitzmann,  established  in 
1873,  which  doctrine  I  advocate,  having  studied  specimens, 
illustrative  of  inflammation  and  suppuration,  under  the  micro- 
scope in  that  investigator's  laboratory. 

24 


354  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

"  Recent  researches  of  botanists  go  far  to  prove  that  even  in 
the  plants  there  exist  no  individual  cells,  but  that  the  interven- 
ing cement-substance,  or  cellulose,  is  traversed  by  minute 
bridges  of  living  matter,  rendering  the  plant  an  individual  from 
the  tips  of  the  leaves  to  the  sporacles  of  the  rootlets.  Eecent 
observers  in  animal  and  vegetable  microscopy  have  drawn,  atten- 
tion to  the  fact  that  by  means  of  certain  reagents  the  nucleus 
will  be  split  up  into  loop-like  threads,  a  process  which  they 
consider  precedes  the  division  of  the  nucleus  and  indirect  divi- 
sion of  the  protoplasm.  This  process  is  termed  karyokinesis, 
or  mitosis, — '  fibrillation,'  '  thread-making.'  This  observation  is 
had  only  with  certain  reagents,  and  is  not  visible  in  tlie  fresh 
specimen  or  in  one  preserved  in  a  chromic-acid  solution.  Sus- 
picion naturally  arises  that  the  loop-like  iigures  of  the  nucleus 
are  artilicially  produced,  and  thereby  their  connections  are  ren- 
dered invisible.  The  threads  forming  the  loops  are  called 
'  chromatin,'  because  they  are  readily  stained  by  aniline  dyes, 
whereas  the  intervening  substance  and  the  protoplasm  itself 
stain  but  little,  and  therefore  are  '  achromatin.'  Facts  ren- 
dered conspicuous  by  staining  applications  only  are  of  doubt- 
ful correctness.  The  fact  that  there  are  threads  and  loops  in 
the  star-point  form  arrangement  in  the  nucleus  rather  proves 
the  latter  to  be  made  up  largely  of  living  matter,  which  is 
known  to  change  shape  any  moment.  Coarse  formations  of 
living  matter  readily  stain  with  aniline  dyes,  whereas  delicate 
formations  of  the  same  substance  will  not  stain.  The  connec- 
tions between  the  loops  of  the  nucleus  and  the  surrounding 
radiating  reticulum  of  the  protoplasm  are  plainly  visible  in 
fresh  specimens,  and  also  those  preserved  in  liquids  which  we 
know  will  not  alter  the  structure  of  protoplasm,  such  as  a  solu- 
tion of  chromic  acid  of  one-tenth  to  one-half  of  one  per  cent. 
Alcohol  as  a  preserving  fluid  is  far  inferior,  owing  to  the  shrink- 
age it  effects. 

"  Whenever  irritation  is  brought  to  bear  upon  a  living  tissue 
reaction  will  follow,  and  this  is  an  inflammatory  process.  The 
first  step  is  liquefaction  of  the  basis-  or  cement^substance, 
probably  induced  by  the  presence  of  an  acid,  likely  lactic. 
Thus  the  living  matter  previously  concealed  (held)  in  the  basis- 
or  cement-substance  becomes  liberated,  and  the  protoplasmic 
form  of  the  basis-substance  reappears.  This  condition  has  been 
observed  directly  by  S.   Strieker  in  the    cornea  of  frogs,    as 


INFLAMMATIOX.  355 

before  stated.  He  saw  the  basis-substance  in  motion,  chauging 
the  configuration  of  its  living  matter,  under  the  microscope, 
much  Uke  clouds  changing  on  the  face  of  the  sky.  Next  the 
protoplasm  furnishing  the  substratum  of  previous  basis-sub- 
stance becomes  split  up  into  small  bodies,  known  as  medullary, 
or  embryonal,  or  inflammatory  corpuscles.  Any  portion  of 
living  matter  of  such  inditferent  bodies  may  grow  to  the  size 
of  a  nucleus,  owing  to  the  presence  of  an  excess  of  pabulum 
beyond  the  physiological  recjuirements  of  these  bodies,  an  ex- 
cess essential  to  the  inflammation.  Not  only  the  original '  cells,' 
but  the  intervening  basis-substance,  will  participate  in  the 
formation  of  new  elements  or  inflammatory  corpuscles.  Here  is 
the  distinguishing  feature  between  modern  and  antique  patho- 
logical views,  for  according  to  the  latter  only  the  '  cells'  them- 
selves were  considered  active  and  capable  of  proliferation." 

At  the  beginning  of  1892,*  P.  Grawitz,  professor  of  morbid 
anatomy  at  the  University  of  Greifswald,  Germany,  published 
an  article,!  followed  by  several  others,  in  which  he  claimed  to 
have  discovered  that  in  the  process  of  inflammation  not  only 
the  cells  of  the  connective  tissue  proliferate,  but  the  basis-sub- 
stance likewise  furnishes  a  large  number  of  cells,  which  he 
termed  slumbering  cells.  Grawitz  believes  that  the  basis-sub- 
stance has  been  developed  from  cells  which  remained  slumber- 
ing until  again  brought  to  view  by  an  irritative  process,  such 
as  inflammation.  E.  O.  Shakespeare,  of  Philadelphia,  in  1882, 
had  previously  written  of  slumbering  cells,  which  he  noticed 
buried  in  the  basis-substance  of  the  cornea.  Quite  recently 
Professor  C.  Weigert,  of  Frankfurt,  Germany,  bitterly  attacked 
Grawitz,!  calling  his  discovery  "  intercellular  pathology,"  in 
contradistinction  to  Yirchow's  cellular  pathology.  He  criti- 
cised Grawitz  that  the  latter  had  ignored  the  researches  into 
inflammation  during  the  last  twenty  years,  and  quoted  Strieker 
as  having  first  discovered  that  during  the  process  of  inflamma- 
tion the  basis-substance  likewise  produces  cells.  IVeigert,  how- 
ever, still  adheres  to  Cohnheim's  emigration  theory,  and  has 

*  This  and  the  following  paragraph,  with  the  illustrations,  are  reprinted  from 
"  The  Doctrine  of  Inflammation,'"  by  C.  F.  W.  Bodecker.  Liternatlonal  Dental 
Journal^  1893. 

-j-  Vi7'choio's  Archiv.     Berliner  Woehensehrift. 

X  Deutsche  Med.  Woehensehrift,  1892. 


356 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


never  admitted  that  the  connective-tissue  cells  do  proliferate. 
He  tries  to  explain  the  images  of  proliferation  by  stating  that 
the  colorless  blood-corpnscles,  or  leucocytes,  creep  into  the 
tissue-cells,  thus   producing   the   appearance  of  proliferation. 


Fig.  200. 


a  '■ 


Diagram  of  the  Inflammatory  Changes  of  Connective  Tissue.    Reduction  op  Basis- 
Substance  TO  Protoplasm  according  to  C.  Heitzmann  (1873). 

A,  inflammatory  changes  of  reticular  cartilage. — a,  increase  of  the  living  matter  in  the  cen- 
tral protoplasmic  bod}',  beginning  reappearance  of  living  matter  in  the  basis-substance;  6, 
territory  composed  of  embryonal  corpuscles,  after  liquefaction  of  basis-substance ;  c,  reappear- 
ance of  nuclei  in  the  basis -substance;  d,  territory  broken  up  to  inflammatory  corpuscles.  B, 
inflammatory  changes  of  fibrous  connective  tissue. — a.  original  protoplasmic  tracts  broken  up  to 
inflammatory  corpuscles ;  b,  fibrous  basis-substance  transformed  to  nucleated  protoplasmic 
bodies,— the  "slumbering  cells"  of  P.  Grawitz ;  c,  inflammatory  infiltration,  all  the  elements 
interconnected  by  threads  of  living  matter. 


Grawitz  admits  that  he  is  ignorant  of  these  researches.  Wei- 
gert,  on  the  contrary,  confesses  the  knowledge  of  Strieker's 
publications,  but  purposely  ignores  them,  because  they  are 
adverse  to  the  doctrine  of  the  cellular  pathology. 


IXFLAMMATIOX.  357 

It  is  remarkable  that  the  German  pathologists  have  arrived 
at  discoveries  which  were  made  twenty  years  ago,  not  by 
Strieker,  as  stated,  but  by  Carl  Heitzmann,  of  Xew  York,  at 
that  time  in  Vienna.  Strieker  himself  publicly  announced  in 
1880  that  he  became  convinced  of  the  correctness  of  the  views 
of  Heitzmann  only  after  six  years  of  hard  work.  He  unques- 
tionably was  the  first  in  Europe  who  acknowledged  (twelve 
years  ago)  the  accuracy  of  Heitzmann's  theory.  The  discovery, 
however,  is  not  his. 

"  The  sum-total  of  the  newly-formed  inflammatory  corpuscles 
is  known  under  the  term  inflammatory  infiltration,  which  means 
that  a  certain  amount  of  a  tissue,  be  it  connective,  muscular,  or 
nerve  tissue,  is  replaced  by  and  transformed  into  newly-appear- 
ing protoplasmic  bodies  in  the  stage  of  indifference, — that  is, 
being  purely  protoplasmic  bodies  without  any  distinctive  tissue 
character  either  as  to  origin  or  destiny.  So  long  as  the  inflam- 
matory corpuscles  remain  in  continuity  by  their  delicate  off- 
shoots they  represent  a  tissue,  though  in  a  condition  of  indiffer- 
ence, or  an  embryonal  state.  Such  a  tissue  by  new  formation 
of  a  basis-substance  will  either  return  to  the  pre^dous  normal 
state,  terminating  the  inflammatory  condition  in  'resolution,' 
or,  being  considerably  augmented  itself,  will  produce  a  tissue 
much  greater  in  bulk  than  the  one  originally  inflamed,  and  we 
^vill  have  hyperplasia. 

'■'■Hyperplasia,  therefore,  appears  when,  in  consequence  of  the 
increase  of  the  living  matter  after  the  new  formation  of  basis- 
substance,  a  certain  bulk  of  tissue  is  formed  in  excess  of  its 
previous  normal  C|uantity.  In  this  condition  the  cells  as  well  as 
the  basis-substance  remain  interconnected  the  same  as  in  the 
production  of  a  normal  tissue. 

"  In  neither  instance  will  the  inflamed  tissue  cease  even  for  a 
moment  to  be  tissue.  The  tissue  which  is  the  bearer  of  the 
blood-  and  lymph-vessels  is  the  connective  tissue,  and  here  is 
the  starting-point  of  inflammation  in  almost  every  instance. 
This  we  understand  from  the  fact  of  the  rather  low  status 
and  activity  of  the  connective  tissue.  We  look  for  the  great- 
est reaction  on  irritation  at  the  sources  of  nutrition,  obviously 
the  blood-vessels.  Muscle,  nerve,  and  epithelial  tissue  react 
in  rather  a  secondary  manner  on  inflammation  of  connective 
tissue. 


358  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

"■  Yircliow  proposed  the  name  '  parenchymatous  inflammation' 
for  the  designation  of  an  inflammatory  process  which  he 
thought  to  be  primary  in  epithelial  structures.  This  term  may 
he  retained  if  restricted  always  to  a  secondary  manifestation 
upon  the  primary  inflammation  of  the  'interstitial'  connectiye 
tissue.  A  gland,  for  instance,  is  a  compound  organ  composed 
of  parenchyma  according  to  Virchovv,  which  is  the  epithelial 
glandular  tissue.  This  is  surrounded  with  and  accompanied 
by  connective  tissue  bearing  many  blood-yessels.  It  is  impos- 
sible that  the  glandular  tissue  could  be  the  primary  seat  of  the 
inflammatory  process.  This  process  will  be  present  in  the 
connectiye  tissue  first,  and  more  or  less  rapidly  inyade  the 
glandular  epithelial  tissue. 

"  If  the  connections  of  the  inflammatory  corpuscles  be  severed, 
we  shall  have  a  certain  number  of  isolated  medullary  or  em- 
bryonal corpuscles  suspended  in  an  albuminous  liquid,  and  this 
we  call  2)us.  Pus  is  therefore  the  resultant  of  destroyed  tissue, 
but  quite  unfitted  for  the  production  of  any  form  of  tissue. 
How  much  the  emigrated  blood-corpuscles  contribute  to  the 
formation  of  pus  may  not  yet  be  positively  stated.  However, 
we  do  know  positively  that  upon  the  approach  of  suppuration 
in  a  certain  tissue  its  blood-vessels  are  destroyed  without  excep- 
tion in  the  territory  involved.  The  blood-vessels,  by  outgrowth 
of  their  endothelia,  become  at  first  solidified  and  afterward 
split  up  into  medullary  and  pus-corpuscles,  the  same  as  all  the 
other  elemental  constituents.  Even  the  smooth  muscles  of  an 
artery  will  partake  of  this  pus-forming  process.  The  number 
of  migrated  leucocytes  cannot  be  great,  considering  the  loss  of 
the  vessels  which  have  supplied  them.  Pus  is  destroyed  tissue, 
first  originating  in  a  closed  cavity  bearing  the  name  of '  abscess'; 
or,  secondly,  coming  from  the  walls  of  physiologically  shut 
cavities,  termed  '  empyema' ;  or,  thirdly,  springing  from  ex- 
posed tissue  surfaces,  viz,  such  as  granulating  surfaces  of 
wounds,  termed  'pyorrhoea.'  In  the  two  latter  instances, 
namely,  empyema  and  pyorrhoea,  the  emigration  of  colorless 
blood-corpuscles  plays,  perhaps,  a  more  important  role  than  in 
the  case  of  '  abscess.'  In  granulating  surfaces  of  wounds, 
especially,  the  source  of  the  pus-corpuscles  may  be  sought 
mainly  in  the  capillaries,  which  abound  in  the  myxomatous 
granulation  tissue,  producing  loops  therein,  upon  the  grouping 
of  which  depends  the  raspberry  look  of  the  so-called  '  proud 


INFLAMMATION.  359 

flesh.'*  Around  an  abscess  a  dense  layer  of  fibrous  connective 
tissue  is  formed  very  soon, — beautifully  displayed  in  alveolar 
abscess  at  the  apices  of  diseased  roots  of  teeth.  This  newly- 
formed  layer  represents  the  productive  activity  of  inflamma- 
tion, being  hyperplastic,  fibrous  connective  tissue,  more  or  less 
well  supplied  with  blood-vessels.  Old  pathologists  termed  this 
layer  '  membrana  pyogena,'  which  signifies  that  the  membrane 
itself  produces  the  pus.  This  view  was  abandoned  long  since, 
and  to-day  the  membrana  pyogena  is  known  to  be  a  secondary 
formation  in  the  appearance  of  an  abscess,  as  it  were,  a  pro- 
tective wall  to  the  healthy  tissues.  After  the  evacuation  of  the 
pus  from  an  abscess  or  an  empyema,  either  by  spontaneous  rup- 
ture of  the  covering  layer  toward  the  surface,  or  artificially  by 
knife  or  caustic,  the  membrana  pyogena  changes  its  character 
and  becomes  the  seat  of  an  acute  inflammation,  which  leads 
to  the  formation  of  a  freely-vascuhirized  myxomatous  tissue. 
This  is  what  is  called  'proud  flesh,'  or  granulation-tissue.  In 
all  instances  of  loss  of  tissue  by  suppuration,  the  final  result  is 
the  formation  of  a  scar.  This  consists  of  a  dense  fibrous  con- 
nective tissue  whose  bundles  freely  interlace,  and  which  is,  as  a 
rule,  scantily  supplied  with  blood-vessels.  It  is  an  outcome  of 
myxomatous  granulation-tissue,  and  is  covered  with  epithelium 
whenever  the  pus  has  been  discharged  through  the  skin  or  a 
mucous  membrane,  which  themselves  appear  to  be  covered  in  a 
normal  condition  with  an  epithelial  layer. 

"  Pus,  therefore,  is  a  tissue  disintegrated  and  broken  up  iuto 
indifferent  or  medullary  corpuscles  which  are  suspended  in  a 
liquid  more  or  less  rich  in  albumin.  The  pus-corpuscles 
remain  alive  as  long  as  the  liquid  surrounding  them  is  sutficient 
for  the  support  of  their  nutrition.  Even  fatty  degeneration  of 
the  pus-corpuscles,  as  seen  in  chronic  abscesses,  will  not  alto- 
gether deprive  them  of  their  vital  phenomena.  Such  corpus- 
cles, if  transferred  upon  a  slide,  remain  amoeboid,  and  they  die 
only  by  exposure  to  a  low  temperature,  or  after  the  addition  of 
chemical  reagents,  or  within  the  body  by  being  deprived  of 
their  nourishing  liquid.  The  last  condition  is  noticed  in  cheesy 
degeneration  of  the  pus  so  often  met  with  in  tuberculosis. 

"A  cpiestion  now  arises :  What  is  the  cause  of  the  formation 

*  Kecent  researches  in  granulating  surfaces  of  the  skin  by  Louis  Heitzmann, 
Archiv.f.  Dennat.,  1892,  have  proved  that  the  source  of  .pus  is  not  the  capillary 
loops,  but  the  outermost  layer  of  the  myxomatous  tissue  itself. 


360  THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

of  pus  ?  Ever  since  the  famous  experiments  of  Cohnheim  and 
Councilman,  vrho  introduced  vials  filled  with  croton  oil  under 
the  skin  of  rabbits,  with  antiseptic  precautions,  and  after  heal- 
ing was  complete  cracked  the  vials,  subcutaneously,  thus  pro- 
ducing an  abscess,  this  is  a  much-mooted  question.  A  host  of 
experimenters,  who  have  repeated  these  trials,  have  taken  views 
pro  and  con  on  the  question.  I  consider  the  experiments  of  P. 
Grawitz  and  W.  deBary,  published  in  Virchow's  Archives,  1887, 
the  most  valuable  testimou}^  toward  settling  the  question. 
They  found  that  the  subcutaneous  injection  of  concentrated 
solution  of  chloride  of  sodium  in  rabbits  and  dogs  was  followed 
by  oedema,  a  swelling  of  the  fascia,  but  no  suppuration.  It 
makes  no  difference  whether  the  solution  contains  a  large  num- 
ber of  staphylococci.  Staphylococcus,  with  its  three  varieties, 
the  Staphylococcus  pyogenes  aureus,  albus,  and  citreus,  first 
discovered  by  Rosenbach,  was  thought  to  be  essential  to  the 
production  of  pus.  And  even  H.  Knapp,  of  New  York,  main- 
tained that  a  small  quantity  of  croton  oil  mixed  with  olive  oil 
will  not  produce  suppuration  if  introduced  into  the  anterior 
chamber  of  the  eye  of  the  rabbit,  whereas  the  same  mixture  if 
contaminated  with  pure  culture  of  Staphylococcus  aureus  will 
invariably  be  followed  by  suppuration  under  like  circumstances. 
Grawitz  and  de  Bary,  on  the  contrary,  have  proved  that  not 
only  the  coccus  named,  but  certain  irritating  reagents  and 
different  products  of  micro-organisms,  not  necessarily  the  sta- 
phylococcus, different  alkaloids,  or  ptomaines,  are  productive 
of  pus.  Solutions  of  nitrate  of  silver,  if  injected  under  the 
skin  of  dogs,  rabbits,  rats,  and  mice,  will  be  harmless  if  weak, 
not  stronger  than  .005  of  one  per  cent.,  but  when  five  per  cent,  in 
strength  will  invariably  be  followed  by  abscess  in  dogs.  JSTeither 
acids  nor  alkalies  cause  suppuration,  except  the  liquor  of  caustic 
ammonia,  which  if  introduced  in  full  strength  is  followed  in- 
variably by  suppuration.  In  neither  of  these  instances  were 
there  an}^  micro-organisms  discoverable  in  the  pus  freshly  re- 
moved from  the  abscess,  or  transferred  upon  nutritive  gelatin 
as  a  culture  medium.  Oil  of  turpentine  did  not  induce  pus  in 
rabbits  and  guinea  pigs,  even  though  injected  in  large  quanti- 
ties, but  only  inflammation ;  whereas  in  dogs  subcutaneous 
injection  of  oil  of  turpentine,  which  is  a  germicide,  was  always 
followed  by  suppuration. 

"  From  these  experiments  it  follows  that  chemical  substances 


INFLAMMATION.  361 

entirely  free  from  bacteria  and  cocci  tend  to  induce  the  suppura- 
tive process  in  ditterent  animals.  On  the  other  hand,  it  has  been 
experimentally  proved  that  in  dogs  and  rabbits  the  injection  of 
cultures  of  staphylococcus  into  the  normal  subcutaneous  tissue 
will  not  induce  inflammation  or  suppuration.  It  is  necessary 
that  a  tissue  first  be  irritated  to  a  condition  of  inflammation,  by 
traumatism  or  by  chemical  irritants,  to  have  a  soil  favorable  for 
the  development  of  staphylococcus,  which  under  these  circum- 
stances will  produce  an  abscess.  Lately  P.  Grawitz  has  shown 
that  the  subcutaneous  injection  of  a  ptomaine  derived  from 
putrescent  organic  material,  cadaverine,  will  always  lead  to  the 
formation  of  an  abscess. 

"  From  the  practical  standpoint  it  is  of  the  utmost  importance 
to  work  aseptically,  or  in  other  words,  with  such  degree  of 
cleanliness  that  the  introduction  of  micro-organisms  or  their 
ptomaines  becomes  impossible.  It  is  well  established  that  even 
open  fresh  wounds,  if  aseptically  dressed  with  gauze  saturated 
with  a  1 :  1000  solution  of  corrosive  sublimate  and  let  alone  for 
a  few  weeks,  will  kindly  heal  without  one  single  droplet  of  pus. 
Corrosive  sublimate  and  carbolic  acid  are  still  most  reliable 
germicides.  We  are  not  yet  prepared  to  assert  that  micro- 
organisms alone  cause  suppuration,  since  there  are  irritating 
chemical  substances  whose  introduction  into  the  body  may 
likewise  be  followed  by  this  process.  Eecent  observers  have 
maintained  that  there  is  a  marked  dilference  between  a  mere 
accumulation  of  leucocytes  and  an  abscess  proper.  In  the  first 
instance  there  may  be  present  a  serous  or  fibrinous  exudate 
entangled  with  a  number  of  emigrated  leucocytes,  without  a 
loss  of  tissue,  without,  therefore,  suppuration.  In  the  latter 
instance  a  certain  amount  of  tissue  is  destroyed  and  directly 
transformed  into  pus.  If  this  view  be  correct,  it  certainly 
strongly  supports  our  present  notions  of  the  process  of  sup- 
puration herewith  laid  down.* 

"  1.  Inflammation  is  a  disturbance  of  nutrition  of  a  tissue 
causing  a  recurrence  of  the  embryonal  condition  of  the  tissue 
involved. 

*  Even  to-day  the  question  whether  or  not  suppuration  is  dependent  upon  the 
presence  of  staphylococci  or  their  ptomaines  is  unsettled.  All,  however,  agree 
that  pus  devoid  of  micro-organisms  is  hland,  harmless,  not  infectious  ;  pus,  on  the 
contrary,  contaminated  with  micro-organisms  possesses  infectious  and  poisonous 
properties  in  a  high  degree. 


362  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

"  2.  The  embryonal  condition  is  established  by  the  breaking 
np  of  the  tissue  into  those  medullary  or  indifferent  corpuscles 
which,  at  an  early  stage  of  normal  development,  have  built  up 
the  tissue. 

"  3.  The  medullary  corpuscles  arise  not  alone  from  the  proto- 
plasmic bodies  of  the  tissue,  the  so-called  '  cells,'  but  the  inter- 
cellular or  basis-substance  is  also  productive  of  such  corpuscles, 
as  these  have  shared  in  the  formntion  of  basis-substance  in  the 
process  of  normal  development. 

"  4.  The  medullary  or  indifferent  corpuscles  will  still  repre- 
sent a  tissue  so  long  as  they  remain  interconnected  and  contin- 
uous. By  the  reappearance  of  basis-substance  simply  the  most 
favorable  termination  is  established,  the  so-called  '  resolution.' 

"  5.  If  the  inflammatory  or  medullary  corpuscles  have  largely 
augmented  in  numbers,  thereby  remaining  in  uninterrupted 
connection,  the  result  will  be  productive  of  a  newly-formed 
tissue  of  increased  size,  a  so-called  '  hj^perplasia.' 

"  6.  Tf  the  inflammator}^  corpuscles  springing  from  previous 
'  cells,'  basis-substance,  and  blood-vessels  break  asunder  and  be- 
come isolated,  they  will  be  suspended  in  an  albuminous  liquid, 
and  will  henceforth  represent  pus-corpuscles. 

"  7.  Pus,  therefore,  is  a  destroyed  tissue  broken  up  into  its 
constituent  elements,  and  as  such  incapable  of  the  production 
of  a  new  tissue,  although  the  single  pus-corpuscles  will  remain 
alive  and  amoeboid  almost  indefinitely  as  long  as  they  are  suflS.- 
ciently  nourished. 

"  8.  The  emigration  of  colorless  blood-corpuscles  may  par- 
ticipate in  the  formation  of  pus. 

"  9.  Suppuration  is  caused  by  the  presence  of  certain  microbes, 
mainly  the  three  varieties  of  staphylococcus,  only  when  a  pre- 
vious intlammation  is  present  in  the  tissue,  furnishing  a  favor- 
able soil  for  the  development  of  the  before-mentioned  microbes. 

"  10.  Staphylococcus  is  not  the  only  antecedent  of  suppura- 
tion, it  having  been  pjroved  by  experiments  that  the  introduc- 
tion of  certain  chemical  agents,  unfavorable  to  the  development 
of  microbes,  ma}^  likewise  be  followed  by  suppuration." 


INFLAMMATION    OF    THE    GUMS -ULITIS.  363 

CHAPTER  XXXII. 

INFLAMMATION  OF  THE  GUMS.-ULITIS. 

To  describe  all  the  diseases  of  the  gums  woiikl  require  a  de- 
lineation of  all  the  lesions  that  affect  the  oral  mucous  mem- 
brane, or  rather  of  the  oral  cavity, — a  task  which  far  exceeds 
the  plan  of  this  work.  I  shall  therefore  contine  myself  to  the 
description  of  only  those  diseases  which  especially  interest  the 
dental  practitioner,  because  in  direct  relation  to  the  teeth. 

In  general  ancemia,  or  chlorosis,  the  gums  appear  bloodless 
and  pale.  Xot  infrequently  they  are  found  in  a  state  of  hydropic 
swelling, — so-called  oedema.  This  condition  may  be  transient, 
arising  from  so-called  catarrhal  stomatitis;  it  may  last  for 
weeks,  as  after  typhoid  fever,  or  for  months,  as  in  pregnancy 
and  after  delivery;  or,  finally,  it  may  depend  upon  a  structural 
change  such  as  is  observed  in  myxcedema  of  the  skin  after  the 
destruction  or  extirpation  of  the  thyroid  body. 

Hyperoemia  of  the  gums  is  caused  by  poisoning  with  mer- 
cury— salivation — or  ^\\i\\  dyes,  as  in  the  manufacture  of  arti- 
ficial flowers,  one  of  the  most  common  offenders  in  the  latter 
case  being  picric  acid.  Sometimes  we  see  the  condition  in 
pregnant  women.  The  slightest  injury  to  the  hyperremic  gums 
causes  bleeding,  which  feature,  together  with  a  bluish-red  color, 
is  symptomatic  of  scurvy. 

Ulitis  (erroneously  termed  gingivitis,  since  the  Latin  word 
gingiva  ouiiht  not  to  be  combined  with  the  Greek  termination 
itis)  is  of  frefpient  occurrence.  It  is  usually  caused  by  mechan- 
ical injuries,  such  as  the  wearing  of  artificial  teeth,  especially 
when  mounted  on  rubber  plates.  In  such  cases  the  pressure 
upon  the  gums  is  assisted  by  a  decomposition  of  the  fluids,  of 
the  mouth  and  the  non-conductivity  of  the  rubber.  Another 
fruitful  source  of  ulitis  is'the  accumulation  of  tartar,  or  salivary 
calculus,  on  the  necks  of  the  teeth,  which  causes  pressure  upon 
the  border  of  the  gums,  resulting  ultimately  in  their  recession 
from  the  teeth.  Decomposing  particles  of  food  at  the  border 
of  the  gums  and  the  tartar,  in  the  space  between  the  gum  and 
the  neck  of  the  tooth,  which  space  is  usually  called  a  pocket, 
and  the  accumulation  of  staphylococci  cause  a  superficial  suppu- 
ration of  the  gum,  which  process,  by  the   destruction  of  the 


364 


THE    ANATOMY    AND    PATHOLOGY    OF   THE    TEETH. 


alveolar  border,  hastens  the  recession  of  the  gum  and  the  ex- 
posure of  the  necks  and  roots  of  the  teeth,  and  induces  perice- 
mentitis. 

The  image  of  acute  ulitis  under  the  microscope  is  rather 
characteristic.  (See  Fig.  201.)  The  fibrous  connective  tissue 
building  up  the  main  mass  of  the  gums  is  found  crowded  with 
inflammatory  corpuscles,  usually  in  nests  or  roundish  foci.  These 
inflammatory  corpuscles  exhibit  greatly  varying  sizes,  from  a 

Fig.  201. 


ACITE   Lliti>5 

COy  row  of  columnar  epithelia  ;  CC7,  cuboidal  epithelia ;  C,  C,  inflammatory  infiltration 
of  fibrous  connective  tissue  ;  T'^,  vacuoled  epithelia,  nucleus  dropped  out.  Magnified  400  diam- 
eters. 


small  solid  and  homogeneous  granule  or  lump  to  a  vacuoled  or 
even  a  granular  and  nucleated  protoplasmic  body.  All  these 
forms  are  known  to  be  ditferent  stages  of  development  of  the 
living  matter.  We  can  easily  satisfy  ourselves  that  not  onh^  the 
protoplasmic  tracts  between  the  bundles  have  produced  inflam- 
matory corpuscles  by  a  process  of  outgrowth  and  splitting  up  of 
the  lumps  of  living  matter,  but  the  bundles  themselves  break  up 


INFLAMMATION    OF    THE    GUMS-ULITIS.  365 

into  rows  of  inflammatory  corpuscles,  obviously  after  the  lique- 
faction of  the  glue-jielcliug  basis-substance.  In  consequence  of 
an  increase  of  the  living  matter,  the  papillae  at  the  surface  of  the 
connective  tissue  are  considerably  enlarged.  The  blood-vessels, 
mainly  the  capillaries  and  veins,  are  seen  widened  and  engorged  • 
with  both  red  and  colorless  blood-corpuscles.  The  stratified 
epithelial  covering  of  the  connective  tissue  likewise  exhibits  an 
outgrowth  and  a  proliferation  of  the  living  matter  in  its  proto- 
plasm. In  mild  cases,  such  as  the  illustration  demonstrates,  only 
the  row  of  columnar  epithelia  and  the  adjacent  cuboidal  epithelia 
show  the  proliferation.  Frequently  the  thorns  of  living  matter 
interconnecting  the  epithelia  by  outgrowth  and  coalescence  pro- 
duce club-  or  pear-shaped  lumps  wedged  in  between  the  enlarged 
epithelia  (L.  Elsberg).  In  higher  grades  of  acute  inflammation 
not  only  the  columnar  but  all  the  cuboidal  epithelia  are  found  to 
be  engaged  in  proliferation.  In  the  latter  the  serous  exudate  fre- 
quently accumulates  around  the  nuclei,  which,  when  they  drop 
out  in  section-cutting,  leave  an  apparently  empty  space, — a  so- 
called  vacuole. 

Suppuration  of  the  gum  is  found  either  superficially  along  the 
borders,  caused  by  the  accumulation  of  tartar,  or  in  the  shape 
of  a  more  or  less  circumscribed  abscess  in  the  depth  of  the 
connective  tissue.  Around  the  abscess  the  gums  are  invariably 
found  in  a  high  grade  of  oedematous  swelling.  The  most  fre- 
quent cause  of  such  abscesses  is  caries  of  the  teeth  combined 
with  purulent  pericementitis.  Sometimes  foreign  bodies, 
splinters  of  bone,  bristles  of  the  tooth-brush,  particles  of  the 
cores  of  apples  or  pears,  etc.,*  cause  abscesses  of  the  gum  when 
a  simultaneous  infection  with  staphylococci  has  taken  place. 

Hi/jjerplasia  of  the  gum  is  always  the  outcome  of  chronic 
plastic  ulitis,  and  is  of  frequent  occurrence.  In  its  mildest 
forms  only  the  papillary  layer  is  rendered  hyperplastic,  the  sur- 
face appearing  to  the  naked  eye  in  the  form  of  lobules  like 
strawberries.  Too  fi'equent  application  of  the  tooth-brush  is 
sufiicient  to  produce  such  a  papillary  hyperplasia.  Higher 
grades  of  chronic  ulitis  are  often  seen  along  the  borders  ot 
carious  canities,  or  covering  deeply-seated  tumors  of  the  jaw  ot 
any  description.  This  process  is  characterized  by  a  new  forma- 
tion of  myxomatous  tissue,  rather  freely  vascularized  and  re- 
placing the  previous  fibrous  connective  tissue.  (See  Fig.  202.) 
The    myxomatous   tissue   in   this   instance   (hyperplastic  gum 


366 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


overlapping  a  cyst)  is  conspicuous  bv  a  large  number  of  proto- 
plasmic tracts  producing  tlie  myxomatous  reticulum  with  large 
spindle-shaped  points  of  intersection.  In  the  meshes  in  the 
middle  of  the  myxomatous  basis-substance  we  frequently  find 


Fig.  202. 


Chronic  Ulitis. 

.1/,  myxomatous  tissue  of  papilla ;  V,  V,  capillary  blood-vessels ;   CO,  CO,  row  of  columnar 
epithelia;  Cf^^,  CO",  cuboidal  epithelia.    Magnified  600  diameters. 


protoplasmic  bodies.  The  capillaries  of  this  tissue  are  con- 
spicuous by  their  large  calibers  and  their  large-sized  endothelia 
along  the  walls.  Most  of  these  blood-yessels  are  newly  formed. 
The  cohimnar  epithelia  directly  covering  the  myxomatous  tissue 


INFLAMMATIOX    OF    THE    GUMS -ULITIS. 


367 


are  still  in  a  state  of  proliferation,  and  here  and  there  we  like- 
wise see  pear-shaped  or  branching  formations  of  living  matter 
in  the  cement-substance. 

The  highest  grades  of  hyperplasia  of  the  gum  are  seen  in 
the  vicinity  of  broken  roots  left  in  the  sockets,  and  in  the  neigh- 
borhood of  large  carious  cavities.  In  the  former  instance  peri- 
cementitis is  the  cause  of  chronic  ulitis,  whereby  lobulated 
tumors  in  the  mucosa  are  produced  sometimes  some  distance 


Fig.  203. 


Htpeeplastic  Gum  GRO'n'x  ixto  the  Caeious  Cavity  of  a  Molar. 

K,  knob  of  gum  of  myxomatous  structure  in  the  carious  cavity  ;  0.  outer  portion  of  gum  ;  F 
(upper),  deep  fissure  caused  by  the  thin  dentinal  wall  of  the  cavity;  E,E.  stratified  epithelium 
on  the  surface ;  F,  varicose  veins  in  myxomatous  tissue,  penetrating  into  epithelial  layer ;  F 
(lower),  fibrous  connective  tissue.    Magnified  100  diameters. 

away  from  the  root.  Tumors  may  even  assume  the  aspect  ot 
cancer,  but  soon  after  the  extraction  of  the  root  they  disappear 
without  further  treatment. 

When  the  gums  overlap  a  large  carious  cavity,  or  when  they 
penetrate  such  a  cavity  through  a  perforation  in  the  thinned 
wall  of  dentine,  they  produce  large  lobulated  tumors,  more  or 
less  filling  up  the  cavity.  It  is  not  always  easy  to  recognize 
hyperplastic  gums  in  the  carious  cavity,  especially  if  the  invasion 


368 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


has  taken  place  through  a  perforation  in  the  dentine  concealed 
from  the  eye.  Hyperplastic  gums  of  this  description  are  of  a 
lobulated  surface,  lively  crimson  red  color,  bleeding  easily,  and 
occasionally  painful.  Fig.  203  illustrates  such  an  instance  of 
hyperplastic  gums,  separated  from  the  outer  portion  by  a  deep 

Fig.  204. 


Hyperplastic  Gum  gro'U'n"  into  the  Carious  Cavity  of  a  Molar. 

H,  flat  epithelia  of  horny  layer;  CU,  cuboidal  epithelia;  CO,  columnar  epithelium  in  oV^lique 
section  ;  M,  myxomatous  connective  tissue ;  V,  V,  varicose  veins  penetrating  into  the  epithelial 
layer.    Magnified  500  diameters. 


fissure,  evidently  caused  by  a  thin  layer  of  dentine  bordering 
upon  the  perforation,  through  which  the  gum  found  its  way 
into  the  carious  cavity.  The  portion  filling  up  the  cavity  is,  to 
a  great  extent,  myxomatous ;  in  the  outer  portion  the  myxoma- 
tous structure  is  present  only  at  the  surface.    A  striking  feature 


INFLAMMATION    OF    THE    GUMS,-ULITIS.  369 

of  the  inner  portion  is  the  presence  of  varicose  veins  at  the  snr- 
face,  penetrating  into  the  stratified  epithelium.  Fig,  204  repre- 
sents this  rather  peculiar  occurrence.  Here  we  see  that  the 
varicose  veins  have,  by  a  gradual  pressure,  destroyed  a  number 
of  epithelia,  bulging  on  the  surface  and  being  covered  only  by  a 
few  layers  of  epithelia.  This  fact  explains  why  gums  in  the 
condition  described  bleed  so  readily  and  so  profusely,  sometimes 
after  the  slightest  injury. 

Ulceration  of  the  r/ums  in  the  shape  of  shallow  losses  of  sub- 
stance, coated  with  a  whitish  exudate,  and  sharply  circumscribed, 
is  not  rare.  Such  ulcers  are  termed  "•  aplitlue^'  popularly  canker 
sores.  Their  etiology,  according  to  E.  Frankl,  is  based  upon 
an  invasion  of  Staphylococci  pj^ogenes  citreus  and  flavus.  In 
regard  to  the  cause  of  this  trouble  but  little  is  known.  Some 
authors  believe  the  disease  to  be  mainly  the  result  of  uncleanli- 
ness,  and  principally  confined  to  childhood,  and  to  those  whose 
food  consists  largely  of  milk.  It  is  certain,  however,  that  derange- 
ments in  the  digestion,  anaemia,  rhachitis,  as  well  as  pregnancy 
and  the  menstrual  period,  greatly  enhance  a  predisposition  to 
the  infection.  The  writer  has  a  patient  who,  almost  every  month 
shortly  before  the  appearance  of  her  monthly  periods,  for  several 
years  was  troubled  with  aphthse.  These  patches  are  most  com- 
monly observed  upon  the  gums  in  the  vicinity  of  the  apices  of 
the  roots  of  cuspids  and  bicuspids,  where  the  mucous  membrane 
of  the  cheek  joins  that  of  the  gums.  They  are  also  seen  under 
the  tongue  on  either  side  of  the  frsenum.  In  the  beo^innins:  we 
notice  them  as  one  or  more  roundish  spots,  about  the  size  of  a 
pin-head.  These  spots  at  first  are  separated  from  one  another 
by  a  dark  red  line  encircling  each  place.  In  later  stages  the 
small  patches  unite  into  one,  usually  assuming  a  more  or  less 
oblong  shape.  The  patients  frequently  complain  of  great  pain 
during  mastication  and  deglutition,  according  to  the  location  of 
the  trouble. 

Si/jyhilis  likewise  causes  ulcers  upon  the  gums,  especially  in 
its  later  stages,  when  shallow  ulcers,  much  resembling  aphthee, 
sometimes  appear  symmetricalh'.  Such  ulcers,  which  likewise 
are  characterized  by  pains  in  the  ingestion  of  acid  foods,  may 
indeed  be  mistaken  for  aphthae.  Even  their  causation  by  syphi- 
lis is  in  many  cases  doubtful.  The  dark-rtd  border  around  the 
ulcer  is  said  to  be  characteristic  of  a  syphilitic  origin.  The 
scars  left   after  the   ulcers   have  healed,   so-called   leiicojjlakia, 

25 


B70      THE  A.N'ATOxMY'  AND  PATHOLOGY  OP  THE  TEETH. 

likewise  in  many  instances  present  an  appearance  wliicli  makes 
the  origin  of  the  trouble  dubious.  Intense  salivation,  following 
the  misuse  of  mercury  in  previous  years,  has  often  led  to  an 
ulcerative  destruction  of  the  gums.  To-da}^  however,  when 
mercury  is  administered  under  great  precautions,  and  saliva- 
tion is  not  allowed  to  pass  beyond  its  initiative  stages,  such  an 
occurrence  is  rare. 

Scurvy  in  its  highest  grades  may  produce  ulcers  on  the  gums, 
characterized  by  a  bluish-red  base  and  easy  bleeding.  The 
oedematous  swelling  around  scorbutic  ulcers  is  always  intense. 

Diphtheritic  ulcers  of  the  gums,  caused  by  a  specific  bacillus 
(Klebs-Lotfier),  are  rarities  ;  so  are  tuberculous  ulcers,  which  are 
caused  by  the  tubercle  bacillus  (Koch). 

Garifireiie  of  the  gum  is  caused  either  by  nowa  or  by  stomatitis. 
It  rapidly  destroys  large  masses  of  tissue,  mainly  at  the  buccal 
surface  of  the  oral  cavity.  The  micro-organism  causing  this 
disease  is  probably  the  same  as  that  of  splenic  fever.  In  intense 
salivation  due  to  overdoses  of  mercury,  and  in  high  degrees  of 
scurvy,  gangrene  of  the  gum  has  likewise  been  observed. 


CHAPTER    XXXIII. 

INFLAMMATION  OF  DENTINE-EBURNITIS.* 

It  is  a  well-known  fact  that  dentine  becomes  the  seat  of  an 
inflammatory  reaction  by  caries,  as  well  as  through  the  gradual 
destruction  of  the  roots  caused  by  alveolar  pyorrhoea,  whereby 
(in  the  latter  instance)  first  the  cementum  and  afterward  the 
dentine  are  destroyed.  Another  instance  of  an  inflammatory 
invasion  of  dentine  is  observed  during  pulpitis,  where  first  the 
secondary  and  afterward  the  primary  dentine  are  destroyed  by 
an  inflammation  of  the  pulp-tissue.  Aside  from  these  secondary 
forms  of  inflammation,  there  occurs  a  primary  inflammation 
in  dentine,  independent  of  pulpitis  or  pericementitis,  running 
its  course  in  the  middle  of  the  dentinal  tissue,  and  leading,  as 

*"  Inflammation  of  Dentine."  By  C.  Heitzmann  and  C.  F.  W.  Bodecker. 
Inde2}endent  Pj'actitioner,  1886. 


INFLAMMATION    OF    DENTINE-EBURNITIS.  371 

all  inflammatory  processes  do,  either  to  a  new  formation  or  to 
destruction  by  suppuration.  This  primary  inflammation  of  den- 
tine is  the  subject  of  this  chapter. 

As  to  the  causes  of  "  eburnitis,"  as  we  propose  to  term  this 
process,  there  are  a  small  number  of  cases  in  which  nothing  can 
be  observed  that  would  account  for  an  inflammatory  reaction  in 
the  dentine,  Avhich,  although  alive,  is  far  away  from  the  blood- 
vessels throughout.  In  a  few  specimens  we  observed  nothing 
anomalous  in  the  soft  parts  surrounding  the  root  of  the  tooth, 
nor  in  the  pulp-tissue.  Some  preparations  exhibited  a  slight 
degree  of  pericementitis,  with  the  characteristic  superficial 
erosions  of  the  cement-tissue.  In  other  cases  we  noticed  a 
layer  of  secondary  dentine,  indicative  of  an  increased  activity 
of  the  pulp-tissue,  although  no  pulpitis  was  ^dsjible.  In  all  cases 
of  eburnitis,  however,  we  observed  in  the  dentinal  tissue  itself 
a  striking  feature :  an  incomplete  calcification  of  the  dentine, 
and  a  great  abundance  of  interglobular  spaces,  signifying  a 
malformation  and  an  incomplete  calcification  of  the  basis-sub- 
stance. This  accounts  for  its  greater  vulnerability  and  suscepti- 
bility to  irritative  processes.  The  enamel,  in  ground  specimens, 
will  likewise  show  abnormalities,  such  as  pigmentation,  stratifi- 
cation, or  insutficient  deposition  of  lime-salts. 

Far  greater  are  the  number  of  inst-mces  in  which  traumatism 
has  led  to  an  inflammation  of  the  dentine.  It  is  evident  that 
any  surgical  interference,  such  as  burring  or  excavating,  will  in 
an  otherwise  normal  dentine  produce  irritation  suflicient  to 
result  eventually  in  an  inflammatory  reaction.  If,  in  addition 
to  excavating,  a  caustic  is  applied  or  a  filling  inserted,  which 
may  exert  a  certain  amount  of  irritation,  infiammation  of  the 
dentine  may  follow. 

"W^e  know,  from  practical  experience,  that  when  a  caustic  in 
the  form  of  an  oxy chloride  or  an  oxyphosphate  filling  is  applied 
to  very  sensitive  dentine,  this  tissue,  in  the  course  of  time,  will 
become  less  sensitive  through  the  partial  obliteration  of  the 
canaliculi  in  the  dentinal  wall  of  the  cavity.  The  filling-material 
in  this  manner  excites  an  irritation,  which  in  the  course  of 
months  or  years  results  in  a  new  formation  of  dentine  around 
the  filling,  and  this  is  often  denser  than  the  original  dentine. 
This  hardening,  as  the  most  favorable  result  of  traumatism,  is 
the  consequence  of  a  reaction  of  the  dentine,  known  under  the 
term  of  consolidation.     On  the  other  hand,  instances  are  not 


372  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

rare  in  which  the  insertion  of  an  oxyphosphate,  oxychloride,  or 
a  gokl  filling  has  given  rise  to  excruciating  pain,  sometimes 
even  necessitating  the  removal  of  the  filling.  The  latter  result 
is  clue  to  intense  irritation  of  the  dentine,  manifested  probably 
through  the  medium  of  the  dentinal  fibers  encroaching  upon 
the  pulp-tissue.  Such  unfavorable  results  are  met  with  mainly 
in  patients  whose  teeth  are  badly  calcified,  or  in  temporary 
teeth,  in  which  the  amount  of  living  matter  is  much  greater 
than  in  the  average  permanent  teeth. 

The  best  known  example  of  the  eftects  of  traumatic  injuries 
upon  dentine  is  seen  in  the  elephant's  tusk  in  which  a  bullet 
has  lodged.  The  remarkable  changes  of  the  dentine  around 
the  bullet  are  well  known  to  scientists  as  well  as  mechanics.  As 
early  as  1798,  the  great  German  poet  and  philosopher,  Goethe, 
investigated  the  subject  of  diseased  ivory  from  the  elephant's 
tusk,  resulting  from  the  impaction  of  iron  or  leaden  balls;  the 
process  appeared  to  him  to  be  a  sort  of  coagulation  (Gerinnung) ; 
he  also  mentions  the  occurrence  of  exostosis  upon  the  wall  of 
the  pulp-cavity,  in  cases  where  a  ball  entered  the  posterior,  weak 
and  hollow  portion  of  the  tooth. 

In  order  to  realize  the  structural  changes  in  inflammation  of 
the  dentine,  let  us  remember  that  it,  like  bone,  is  a  living  tissue. 
The  analogy  between  these  two  tissues  is  clearly  established  by 
the  fact  that  in  the  development  of  bone-tissue  we  observe 
globular  territories,  the  same  as  in  the  formation  of  dentine.. 
In  the  former  instance  every  territory  contains  one  or  more 
bone-corpuscles,  with  their  offshoots  (lacunae  and  canaliculi), 
whereas  in  the  dentine  the  territories  are  pierced  by  the  canali- 
culi and  their  tenants,  the  dentin akfibers.  The  basis-substance 
in  both  these  tissues  is  traversed  by  a  large  amount  of  living 
matter,  in  the  shape  of  a  delicate  reticulum,  the  meshes  of 
which  are  filled  with  the  calcified  basis-substance  proper.  The 
study  of  the  history  of  development  of  bone  and  dentine  reveals- 
a  strikino;  similaritv  in  the  formation  of  both  of  these  tissues. 
The  osteoblasts  are  preliminary  formations  in  developing  bone- 
tissue,  in  the  same  manner  as  are  the  odontoblasts  at  the 
periphery  of  growing  dentine.  All  attempts  to  explain  the 
development  of  dentine  directly  from  the  odontoblasts  have 
proved  unsuccessful,  as  neither  the  formation  of  the  basis-sub- 
stance nor  that  of  the  dentinal  fibers  could  ever  be  brought  in 
accordance    with    the    elongated     odontoblasts,    whereas    the- 


IXFLAMMATIOX    OF    DENTINE-EBURXITIf 


373 


development  of  the  dentine  becomes  plain  if  we  take  tlie 
ground  that  tlie  odontoblasts  break  up  into  medullary  corpus- 
cles, between  Avhich  the  dentinal  fibers  are  formed.  If  the 
odontoblasts  should  calcify  directly,  we  would  be  at  a  loss  to 
understand  the  formation  of  globular  territories  in  fully-dey el- 
oped dentine.  If,  on  the  contrary,  we  accept  the  formation  of 
basis-substance  from  medullary  corpuscles,  the  appearance  of 
globular  territories  becomes  plain.  Il^othing  is  required  but  a 
group    of  medullary   corpuscle^,  which    are   transformed  into 

YxG.  205. 


Ebcrxitis.    Xeck  of  Tooth. 

C,  eementum,  with  shallow  excavations  at  its  periphery,  caused  by  pericementitis;  J>.  den- 
i;ine  in  the  beginning  of  dissolution  of  lime-salts;  E,  pr  'toplasmic  masses  in  globular  territories. 
Magnified  200  diameters. 


basis-substance,  while  the  larger  threads  of  living  matter, 
known  as  Tomes's  tibers,  traverse  the  rows  of  medullary  cor- 
puscles, taking  their  course  between  ihem.  Six  years'  study  of 
the  history  of  development  of  the  teeth,  especially  of  specimens 
of  the  sixth  month  of  intra-aterine  life,w]ien  dentine  begins  to 
form,  has  led  to  the  con^ac  ion  stated  above. 

Inflammation "  causes  a  solution  of  the  lime-salts,  and  after- 
ward a  liquefaction  of  the  basis-snbstance,  both  in  bone  and 
dentinal  tissue.     The  result  will  be  the  appearance  of  globular 


374  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

spaces,  or  bay-like  excavations,  which,  instead  of  being  filled 
with  basis-substance,  exhibit  mednllaiy  corpuscles,  or  multinu- 
clear  protoplasmic  masses,  corresponding  to  the  embryonal 
stage  of  the  inflamed  tissue.  (See  Fig.  205.)  The  excavations 
of  the  dentine  are  identical  with  those  seen  in  the  process  of 
absorption  of  the  dentine  of  temporary  teeth,  and  those  of  sec- 
ondary dentine  in  the  neighborhood  of  an  inflamed  pulp.  The 
diagnosis  of  primary  eburnitis  becomes  established,  not  by  the 
appearance  of  such  excavatioi^s,  but  by  their  presence  in  the 
middle  of  the  dentine  without  any  connection  with  the  surface, 
or  with  the  pulp-chamber  of  the  tooth. 

The  earliest  feature  of  eburnitis  under  the  microscope  is  the 
appearance  in  the  middle  of  the  dentine  of  bay-like  excavations 
of  varying  sizes,  and  separated  from  one  another  by  glistening 
ledges.  At  first  the  dentinal  canaliculi  and  their  tenants  (the 
Tomes  fibers)  remain  recognizable  within  the  basis-substance. 
In  the  next  stage  only  dentinal  fibers  remain  discernible,  the 
contours  of  the  canaliculi  being  lost,  while  the  basis-substance 
itself  looks  irres'ularlv  o-ranular.  The  difi^erence  in  the  refrac- 
tion  of  light  of  these  globular  spaces,  as  compared  with  normal 
dentine,  indicates  a  dissolution  of  lime-salts  within  them.  In  a 
still  later  stage  the  entire  basis-substance  is  transformed  into  a 
granular  mass,  which  is  easily  stained  by  an  ammoniacal  solu- 
tion of  carmin.  The  globular  spaces  appear  to  be  filled  with 
multinuclear  protoplasmic  masses,  or  with  a  number  of  medul- 
lary corpuscles,  more  or  less  coarsely  granular,  and  flattening 
each  other  to  some  extent.  These  features,  therefore  (as  men- 
tionedj,  are  identical  with  those  observed  in  absorption  of  tem- 
porary teeth,  the  only  difference  being  that  the  latter  process 
starts  from  the  periphery,  whereas  eburnitis  begins  in  the  mid- 
dle of  the  dentine,  without  any  direct  connection  with  the  outer 
surface  or  the  pulp-cavity  of  the  tooth,  and  often  at  the  border 
of  cavities  that  have  been  previously  filled.     (See  Fig.  206.) 

The  origin  of  the  globular  fields  of  dissolution  in  temporary 
teeth,  in  some  instances,  may  be  questioned,  since  it  is  admitted 
that  they  are  simply  the  results  of  the  dissolution  of  the  lime- 
salts,  while  their  filling  in  with  medullary  corpuscles  may  be 
caused  b}' immigration  from  without.  But  in  most  of  the  speci- 
mens of  eburnitis  which  we  have  examined,  no  doubt  was  left 
as  to  the  primary  origin  of  the  spaces  and  their  contents  within 
the  dentine,  for  many  of  them  were  isolated,  and  sometimes  far 


IXFLAMMATION    OF    DE^'TIXE ,-EBURNITIS. 


375 


apart  from  the  original  seat  of  inflammation  and  far  from  the 
pulp-chamber  as  well  as  the  periphery  of  the  tooth.  In  connec- 
tion with  eburnitis  we  have  noticed  frequently  that  the  crowns 
of  teeth  thus  affected  were  surrounded  by  defective  enamel. 
There  can  be  no  doubt  that  the  medullary  corpuscles  present  in 
these  spaces  have  really  grown  from  dentinal  tissue,  respectively 
from  the  living  matter  of  the  dentinal  fibers  and  of  the  basis- 
substance. 

Fig.  206. 


Eburxitis.    Ceottx  of  Molar. 

JJ,  beginning  dissolution  of  lime-salts  in  the  middle  of  dentine  :  M.  medullary  corpuscles  fill- 
ing the  globular  spaces  that  have  arisen  from  inflamed  territories  of  dentine  ;  C,  cavity  in  the 
dentine,  whose  contents  had  been  dragged  out.    Magnified  500  diameters. 

Tn  some  of  the  specimens,  especially  in  the  central  portions 
of  somewhat  larger  cavities,  the  medullary  tissue  had  been 
removed  by  the  process  of  grinding  or  cutting.  Where,  how- 
ever, they  had  been  leit  in  situ,  the  medullary  corpuscles 
appeared  interconnected  by  means  of  delicate  offshoots,  repre- 
senting an  embryonal  tissue;  or  no  distinct  boundary  lines  were 
seen  between  the  medullary  corpuscles,  the  whole  filling  of  a 
globular  territory  being  a  uniformly  granular  protoplasmic 
mass,  with  interspersed  nuclei.    We  cannot  deny  the  possibility 


376  THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

that  by  tlie  breaking  apart  of  tliese  medullan-  corpuscles  pns 
may  be  formed  in  the  middle  of  the  dentine,  thus  representing 
an  abscess  independently  of  the  pulp-tissue.  Wedl  and  Al- 
brecht  take  the  presence  of  blood-vessels,  presumably  grown 
into  the  dentine  from  the  pulp,  for  an  absolute  necessity  in 
cases  of  abscess  of  th'e  dentine,  ^uch  a  presumption  is  super- 
fluous, in  our  opinion,  for  we  assert  the  dentine  to  be  a  living 
tissue,  and  as  such  capable  of  primary  inilammation,  nay,  sup- 
puration, without  the  direct  co-o]ieration  of  blood-vessels.  We 
fully  believe  in  the  possibility  that  a  so-called  pyogenic  mem- 
brane could  even  form  around  the  abscess  without  a  direct  sup- 
■ply  of  blood-vessels.  If  it  is  claimed  that  an  abscess  in  the 
dentine  must  form  originally  in  connection  with  the  pulp-tissue, 
and  afterward  be  separated  from  the  latter,  we  deny  any  such 
necessity,  since  we  claim  the  possibility  of  the  formation  of  a 
primary  abscess  in  the  dentine,  independenily  of  the  pulp-tissue. 

Far  more  common  than  suppuration,  however,  is  the  healing 
process  of  eburnitis,  the  results  of  which  may  be  either  a  new 
formation  of  dentine,  closely  resembling  secondary  dentine,  or  a 
dentine  which  is  destitute  of  canaliculi,  representing  what  some 
authors  have  termed  osteo-dentine.  We  meet  with  places  in 
the  dentine,  more  especially  in  the  neighborhood  of  fillings  of 
some  years'  standing,  wherein  the  dentine  is  largely  composed 
of  calcified  basis-substance,  and  the  dentinal  canaliculi  are 
arranged  in  bundles  more  or  less  separated,  but  of  a  normal 
appearance.  It  is  obvious  that  here  the  recalcification  of  the 
previously  inflamed  dentine  was  most  perfect,  producing  a 
tissue  which  is  harder  and  richer  in  lime-salts  than  the  original 
dentine. 

In  another  instance,  the  newly-formed  tissue  closely  resembles 
secondary  dentine,  with  few,  irregularly-scattered,  wavy  canali- 
culi, and  large  territories  of  calcified  basis-substance,  destitute 
of  canaliculi.  Sometimes  the  basis-substance  may  be  uniform 
in  structure,  or  composed  of  globular  fields  or  territories.  The 
tissue  as  such  under  the  microscope  could  not  be  distinguished 
from  secondary  dentine;  the  fact,  however,  that  it  is  found  far 
from  the  pulp-chamber,  in  the  middle  of  otherwise  normal  den- 
tine, proves  that  it  is  the  result  of  a  previous  inflammatory 
process  of  the  dentine.  Here  the  calcification  still  attained  a 
high  degree  of  perfection,  so  desirable  from  the  practical  stand- 
point, although  morphologically  not  as  perfect  as  in  the  first 


INFLAMMATION    OF    DEXTIXE-ECURNITIS. 


377 


instance.  Fig.  207  illustrates  this  form  of  healing  process  in 
eburnitis.  Here  the  cavity,  whose  soft  medullarj  contents  had 
been  dragged  out  in  the  process  of  grinding,  is  surrounded  by 
a  tissue  bearing  all  the  characteristics  of  secondary  dentine. 

Another  result  of  eburnitis  is  the  re-formation  of  the  basis- 
substance,  composed  of  small  globular  masses,  between  which 
are  visible  irregular  and  widened  canaliculi.  It  is  obvious  that 
calcification  in  this  instance  is  deficient,  and  consequently  the 
newly-formed  dentine  is  less  consistent  than  normal  deutine. 
In   one  of  our  specimens,  dentine  of  a   temporary  tooth,   we 


Fig.  207. 


Healing  OF  Eburxitis.    Crowx  of  Molar. 

C,  empty  cavity  ;  M,  medullary  tissue,  at  the  border  of  the  cavity,  partly  calcified ;   S,  sec- 
ondary dentine,  with  scanty  and  irregularly-scattered  canaliculi.    Magnified  100  diameters. 

observed,  not  far  apart  two  spots,  one  of  which  shows  a  large 
amount  of  basis-substance,  with  scanty  and  narrow  canaliculi, 
whereas  another  spot  was  in  the  condition  before  described, — 
viz,  imperfectly  calcified.  The  latter  portion  exhibited  well- 
marked  globular  territories  all  around  a  cavity,  which  probably 
contained  medullar}^  tissue,  before  subjection  to  the  process  of 
grinding.  Some  territories  contain  numerous  and  wide  canali- 
culi, others  scarcely  any.  Crystals  of  hsematoidin  indicate  the 
inundation  of  the  inflamed  tissue  with  blood,  in  the  acute  stas^e. 


378 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


As  this  cavity  was  near  the  pulp-chamber,  the  sataration  of  the 
tissue  in  consequence  of  a  hemorrhage  is  explicable,  (See  Fig. 
208.) 

In  a  fourth  instance  of  eburnitis  the  healing  process  is  rather 
poor.  JSTo  new  canaliculi  are  formed,  but  the  whole  field  is 
traversed  by  irregular,  angular,  branching  spaces,  with  numer- 
ous radiating  offshoots,  bearing  a  close  resemblance  to  bone- 
corpuscles.  The  presence  of  such  spaces  gave  rise  to  the  term 
"  osteo-dentine,"  applied  by  previous  authors.     We  would  agree 


Fig.  208. 


Healing  of  Eburnitis.    Crown  op  Bicuspid. 

C,  cavity  bounded  by  globular  territories,  between  which  there  are  uncalcified  interglobular 
spaces;  ^S",  secondary  dentine;  H,  crystals  of  rust-brown  haematoidin.   Magnified  500  diameters. 

with  this  term  if  the  restriction  be  added,  that  in  these  instances 
no  regular  bone-tissue  is  combined  with  dentine,  but  only  a 
tissue  resembling  bone.  The  spaces  are  filled  either  with  medul- 
lary corpuscles,  or  a  homogeneous  basis-substance,  or  highly  re- 
fracting globular  masses,  the  result  of  a  recent  but  rather  imper- 
fect deposition  of  lime-salts.  The  basis-substance  between  these 
spaces  is  likewise  composed  of  globular  calcified  masses,  between 
which   we   observe   branching   offshoots   of   the   spaces.     The 


INFLAMMATION    OF    DENTINE -EBURNITIS. 


379 


periphery  of  a  spot  of  healed  eburuitis  may  show  small  spaces 
scantily  scattered  in  the  basis-substance,  whereas  the  central 
portions  may  exhibit  very  large  spaces  and  comparatively  little 
basis-substance.  Fig.  209  illustrates  such  a  termination  of  ebur- 
nitis,  one  portion  showing  a  tolerably  well-developed  secondary 
dentine,  other  portions  a  poorly-calciiied,  so-called  osteo-dentiiie, 
in  which  the  peripheral  zones  are  decidedly  richer  in  lime-salts 
than  the  central  ones.     Evidentl}^  the  healing  process  of  eburnitis 

Fig.  209. 


Healing  Process  op  Ebuexitis.    Root  of  Molar. 

B,  secondary  dentine,  Tpith  scantj'  canaliculi  and  a  globular  basis-substance  ;  S,  spaces  re- 
sembling bone-corpuscles,  with  very  irregular,  branching  offshoots  ;  G,  globular  depositions  of 
lime-salts  in  the  basis-substance.    Magnified  500  diameters. 


is  poorest  in  the  last  instance,  leading,  as  it  were,  to  the  forma- 
tion of  a  comparatively  soft,  brittle,  and  crumbling  dentine, 
lacking  the  elasticity  of  the  original  tissue,  and  not  entitled  to 
the  name  of  dentine  proper.  From  the  description  given  of 
healed  eburnitis  around  gun-balls  in  elephants'  tusks,  it  is  ob- 
vious that  the  mass,  as  described  as  a  result  of  "consolidation" 
or  "coagulation,"  etc.,  is  such  a  poorly-calcified  dentine,  or 
osteo-dentine. 


380       THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH. 

CHAPTER   XXXIY. 

PULPITIS  IN  ITS  CLINICAL  ASPECTS. 

Many  disturbances,  such  as  certain  forms  of  pericementitis, 
necrosis,  etc.,  are  the  result  of  primary  pulpitis  that  has  caused 
the  death  of  the  dental  pulp.  The  pain  which  usually  accom- 
panies pulpitis  is,  as  a  rule,  severe,  though  not  always  localized. 
The  dental  pulp  being  richly  supplied  with  nerve-fibers  and 
blood-vessels,  at  the  same  time  inclosed  in  an  unyielding  wall 
of  dentine,  is  unable  to  swell.  Even  a  comparatively  slight 
inflammation  may  cause  considerable  pressure  upon  the  nerve- 
fibers, — pressure  which  manifests  itself  either  as  pain  in  the 
afifected  tooth,  or  as  neuralgia  in  other  parts  of  the  nervous 
system.  The  severity  of  the  pain  in  pulpitis  is  not  so  much 
dependent  upon  the  changes  occurring  in  the  pulp-tissue,  as 
upon  external  influences  and  constitutional  peculiarities  of  the 
patient.  We  often  meet  with  pulps  in  wdiich  the  inflammation 
is  slight,  while  the  pain  caused  thereby  is  severe.  On  the  other 
hand,  we  observe  cases  in  which  even  an  extensive  pulpitis 
causes  comparatively  little  or  no  pain.  Occasionally  we  see 
patients,  most  of  whose  teeth  are  broken  and  decayed,  who  de- 
clare, nevertheless,  that  they  have  never  had  toothache,  while 
in  other  instances  patients  sufier  pain  as  soon  as  the  caries  has 
penetrated  the  enamel  of  the  tooth. 

The  etiology  of  pulpitis  may  be  classified  under  the  following 
heads : 

Dental  caries ; 

Invasion  of  the  pulp  by  micro-organisms  (staphylococci  and 
streptococci) ; 

Pressure  of  filling-materials  placed  too  near  the  pulp; 

Mechanical  violence,  or  traumatism; 

Fracture  of  the  tooth; 

Pericementitis ; 

'New  formations  in  the  pulp- tissue; 

Constitutional  disturbances ; 

Sudden  thermal  changes ; 

Electrical  shock. 

The  exciting  cause  of  pulpitis  may  be  one  of  the  above  cate- 
gory of  causes,  or  a  combination  of  several  of  them.  The 
most  frequent  is  unquestionably  caries.    In  the  process  of  caries 


PULPITIS    IN    ITS    CLINICAL    ASPECTS.  381 

miero-oro;anisins  in  tlie  dental  canaliculi  enter  in  advance  of 
the  zone  of  decalcification,  and  this  explains  the  occurrence 
of  inflammation  in  pulps  which  are  not  as  yet  exposed.  In 
many  instances  we  find  that  the  dentine  covering  the  pulp  in  a 
carious  cavity  is  C[uite  hard,  and  one-half  of  one  millimeter,  or 
even  more,  in  thickness.  ^N^evertheless,  should  the  tooth  be 
extracted,  we  may  meet  with  an  inflamed  pulp  in  it.  In  this 
instance  the  exciting  cause  is  an  invasion  of  micro-organisms 
into  the  pulp-tissue  through  the  portion  of  the  dentine  covering- 
the  pulp  in  the  vicinity  of  the  carious  cavity.  Sometimes  this 
layer  of  dentine  is,  though  thin,  quite  healthy,  and  a  gold  filling 
hammered  into  the  cavity  may  produce  inflammation  of  the 
pulp,  not  only  by  reason  of  the  pressure  exerted  in  the  intro- 
duction of  the  filling,  but  also  through  the  thermal  changes 
resulting  from  the  contact  of  the  metal  with  the  thin  layer  of 
dentine  covering  the  pulp.  The  same  may  be  the  result  after 
the  introduction  of  an  amalgam  filling  under  the  above  condi- 
tions. The  irritation,  however,  will  be  much  greater  should  the 
filling-material  be  oxychloride  or  oxyphosphate  of  zinc.  In  the 
latter  instance,  as  soon  as  the  filling  is  introduced,  the  patient 
usually  experiences  considerable  pain,  which  may  last  from  one 
hour  to  one  or  two  daj's,  or  until  the  filling-material  is  removed. 

Exceptionally  we  may  induce  pulpitis  in  the  process  of  regu- 
lating teeth,  when  the  force  employed  has  been  too  great  or 
too  rapid.  Pulpitis  may  be  the  result  of  a  heavy  or  too  long- 
continued  malleting  in  the  introduction  of  gold  fillings,  or  of 
the  driving  of  wooden  or  metallic  wedges  between  the  teeth. 
We  also  observe  pulpitis  in  consequence  of  traumatisms,  when 
portions  of  the  crown  of  a  tooth  are  broken  ofi:',  and  the  pulp 
becomes  more  or  less  exposed.  New  formations  of  bone  or 
dentine — so-called  pulp-stones — sometimes  become  a  source  of 
irritation  to  the  pulp-tissue.  As  a  rule,  so  long  as  these  newly- 
formed  tissues  are  developed  upon  the  walls  of  the  pulp-chamber 
in  contact  with  the  primary  dentine,  they  do  not  cause  irrita- 
tion. Quite  diflerent,  however,  is  the  outcome  of  new  forma- 
tions of  bone  or  dentine,  when  thev  originate  in  the  middle  of 
the  pulp-tissue,  in  which  situation  they  often  produce  pulpitis. 
They  may  give  rise  to  neuralgia  which  frequently  is  obscure 
and  more  pronounced  in  other  parts  of  the  nervous  system  than 
in  the  affected  dental  pulp. 

Constitutional  disturbances,  especially  those  interfering  with 


382  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

the  circulation  of  the  blood,  occasionally  produce  pulpitis. 
Among  these  I  would  mention  anaemia  as  the  most  frequent. 
In  circumscribed,  pericementitis  the  inflammatory  infection  may 
reach  the  apex  of  the  root  of  a  tooth,  and  thus  induce  pulpitis. 
Heat,  cold,  and  electricity  are  remedial  agencies  frequently  em- 
ployed to  abate  inflammation,  but  when  applied  to  the  teeth  in 
higher  degrees,  or  suddenly,  they  also  may  produce  pulpitis. 

To  the  dental  practitioner  it  is  of  the  utmost  importance  to 
be  able  to  make  a  correct  diagnosis  of  the  diseases  of  the  pulp, 
that  he  may  decide  upon  the  proper  mode  of  treatment.  First 
of  all,  it  will  be  necessary  to  classify  the  diseases,  in  order  to 
diflerentiate  between  them.  For  this  purpose  most  of  the 
classiflcations  of  pulpitis  are  rather  unsatisfactory.  From  a 
pathological  point  of  view,  we  have  to  consider  only  two  prin- 
cipal forms  of  inflammation, — viz,  the  acute  and  the  chronic. 
From  a  clinical  standpoint,  on  the  other  hand,  it  is  advisable 
to  formulate  a  more  definite  classification  of  the  diseases  of 
the  dental  pulp.  Adolph  Witzel*  distinguishes  varieties  of 
pulpitis  in  the  following  manner:  1.  Irritation  of  the  pulp,  or 
primary  hypereemia ;  2.  Partial  pulpitis;  3.  Total  pulpitis  with 
abscess ;  4.  Suppuration  and  fatty  degeneration  of  the  pulp ; 
5.  Inflammatory  gangrene  of  the  pulp.  The  classification  of 
J.  Arkovy,t  in  Europe,  has  been  accepted  by  several  of  the 
later  writers.  He  was  the  first  to  state  that  most  of  the  dis- 
eases of  the  pulp  originate  independently,  while  formerly  it  was 
believed  that  all  chronic  forms  of  pulpitis  developed  from  a 
primary  acute  inflammation.  Arkovy's  classification  is  as  fol- 
lows:  I.  Acute  pi dpiiis.  I.  Septic  superficial  acute  pulpitis ;  2. 
Partial  acute  pulpitis;  3.  Total  acute  pulpitis;  4.  Purulent 
partial  acute  pulpitis  :  5.  Acute  traumatic  pulpitis.  II.  Chronic 
pulpitis.  1.  Chronic  parenchymatous  pulpitis ;  2.  Chronic  total 
purulent  pulpitis;  3.  Chronic  hypertrophy  of  the  pulp  :  a,  gran- 
ular, 6,  sarcomatous;  4.  Gangrene  of  the  pulp;  5.  Total  gan- 
grene of  the  pulp:  6.  Chronic  idiopathic  pulpitis  {s.  concre- 
mentalis). 

The  pathology  of  the  process  of  irritation   has  been  dwelt 
upon  in  Chapter  XXV,  without  reference  to  its  clinical  aspect. 


*  "Die  Antiseptische  Behandlung  cler  Pulpakrankheiten."     Berlin,  1879  ;  and 
"  Compendium  der  Pathologie  und  Therapieder  Pulpakrankheiten."     Hagen  in 

t  "Diagnostik  der  Zalmkrankheiten."     Stuttgart,  1885. 


PULPITIS    IN    ITS    CLINICAL    ASPECTS.  383 

While,  from  a  pathological  point  of  view,  we  cannot  embrace 
this  process  in  the  chapter  on  pulpitis,  clinically  considered  it 
belongs  in  the  latter  chapter.  Arkovy  and  Rothmann  classify 
irritation  of  the  pulp  as  pulpitis,  and  call  it  "  acute  septic  superfi- 
cial pulpitis.'''  I  cannot  agree  with  them,  as  the  word  pulpitis 
implies  a  process  in  which  the  pulp-tissue  undergoes  marked 
changes,  visible  under  the  microscope.  The  process  which  both 
these  authors  describe  as  acute  septic  superiicial  pulpitis  does 
not,  according  to  their  description,  exhibit  any  tissue-changes  in 
the  pulp,  but  merely  an  invasion  of  micro-organisms,  and  is, 
therefore,  in  strictness,  nothing  but  an  irritation  of  the  pulp. 
I  therefore  agree  with  Witzel  and  Baume  as  to  this  point,  and 
will  call  this  disturbance  "  irritation  of  the  pulp,''  though  for 
convenience  in  a  clinical  consideration,  I  shall  classify  it  with 
pulpitis.  According  to  general  principles  in  morbid  anatomy,  we 
will  classify  diseases  of  the  pulp  under  the  following  headings : 

I.  Irritation  of  the  Pulp. 

II.  Acute  Pulpitis. 

1.  ITon-purulent. 
a.  partial. 

h.  total. 

2.  Purulent. 

a.  partial. 

b.  total. 

III.  Chronic  Pulpitis. 

1.  Hyperplastic. 
a.  partial. 

h.  total. 

2.  Purulent. 
a.  partial. 
h.  total. 

lY.  Gangrene  of  the  Pulp. 

a.  moist. 

h.  dry. 
Y.  Degenerations  and  Atrophies  of  the  Pulp. 

a.  calcifications. 

b.  eburnification  and  ossification. 

c.  sclerotic  atrophy. 

d.  reticular  atrophy. 

e.  fatty  degeneration. 
/.  pigmentation. 


384      THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH. 
I.  IRRITATION  OF  THE  PULP. 

When  caries  approaches  the  pulp-chamber,  irritatiou  of  the 
pulp  ensues.  A  tooth  may  decay,  and  the  process  reach  a 
small  portion  of  the  pulp-chamber,  yet  the  pulp  may  not  react 
beyond  the  stage  of  irritation.  The  same  conditions  some- 
times occur  in  teeth  affected  by  mechanical  abrasion  and  erosion. 
Fracture,  mechanical  violence  to  the  teeth,  or  pericementitis 
may  likewise  irritate  the  pulp.  Quite  frequently  this  trouble 
originates  from  eburnification  and  ossification  of  the  pulp- 
tissue,  the  pathological  anatomy  of  which  is  described  in  Chap- 
ter XXVI.  Constitutional  disturbances  also  are  known  to  have 
the  same  effect  upon  the  pulps,  and  sometimes  even  in  teeth 
without  mechanical  abrasion,  erosion,  or  carious  defects. 

Diagnosis. — The  affected  teeth  may  be  slightly  sensitive  in 
mastication;  if  decayed,  the  cavity  rarely  extends  to  the  pulp- 
chamber,  the  layer  of  dentine  interposed  between  pulp  and 
carious  cavity,  although  quite  thin,  being  usually  hard.  In  rare 
instances  the  pulp  may  be  exposed  on  one  of  its  horns  by  caries, 
and  apparently  but  irritated,  when,  nevertheless,  slight  pressure 
upon  it  by  means  of  a  piece  of  cotton  produces  but  momentary 
pain. 

The  suhjectice  phenomena  of  irritation  of  the  pulp  are  char- 
acterized by  intermittent,  sub-acute,  drawing  pain,  mostly  last- 
ing a  few  minutes  at  one  time.  The  pain  usually  originates 
suddenly,  when  the  tooth  comes  in  contact  with  anything  hot, 
cold,  salty,  sweet,  or  sour,  or  when  foreign  substances  are 
pressed  into  the  carious  cavitj^.  The  crowns  of  teeth  not  being 
affected  by  caries,  erosion,  or  mechanical  abrasion,  the  pulps 
being  irritated  by  pulp-stones,  or  in  consequence  of  constitu- 
tional derangements,  the  patients  mainly  complain  of  a  sensa- 
tion of  uneasiness  in  all  the  teeth  or  the  jaw  of  the  affected  side. 
This  sensation  may  sometimes  be  associated  with  slight  neuralgic 
pains  in  other  parts  of  the  nervous  system. 

Differential  Diagnosis. — There  are  two  diseases  of  the  pulp 
showing  symptoms  somewhat  similar  to  those  of  irritation  of  the 
pulp, — viz,  acuf.e  partial  pulpitis,  and  sclerotic  atrophg  of  the  jJ alp. 
Acute  partial  pulpitis,  however,  rarely  exists  unless  the  pulp  be 
exposed  by  caries,  except  when  irritation  is  due  to  pulp-stones 
or  constitutional  disturbances,  which  frequently  occur  in  other- 
wise sound  teeth.  In  the  latter  case,  it  is  not  always  possible  to 
state,  with  any  degree  of  certainty,  whether  a  pulp  be  merely 


PULPITIS    IN    ITS    CLINICAL    ASPECTS.  600 

irritated,  or  whether  slight  partial  acute  pulpitis  be  present. 
When  the  attected  tooth  contains  a  carious  cavity,  it  should  be 
carefully  examined,  especially  in  the  vicinity  of  the  horns  of 
the  pulp,  which  will  usually  lead  to  the  proper  diagnosis. 

Sclerotic  atrophy  of  the  pulp  also  may  be  confounded  with 
irritation  of  the  pulp,  but  clinically  we  are  unable  to  differen- 
tiate between  these  two  diseases. 

The  profjnosis  of  irritation  of  the  pulp  is  quite  favorable  in 
carious  teeth,  as  the  removal  of  the  cause,  by  disinfecting  and 
fillina"  the  cavitv,  alwavs  effects  a  cure,  although  Arkovv  men- 
tions  that  sometimes  afcer  filling  teeth  whose  pulps  have  been 
irritated,  partial  or  total  gangrene  may  follow, — a  result  which 
the  writer  never  has  observed. 

II.  ACUTE  PULPITIS. 

1.  Non-Purulent. — a.  Partial  Acute  Pulpitis. — Diagnosis. — 
In  a  pulp  slightly  exposed,  an  acute  partial  inflammation  usually 
results.  After  the  removal  of  the  carious  dentine  from  the 
cavity  of  the  tooth,  we  can  easily  ascertain  if  the  pulp  has  be- 
come exposed  in  a  small  place,  the  exposure  usually  being 
situated  over  one  of  the  horns.  In  a  few  instances  the  pulp 
may  still  be  found  covered  by  a  very  thin  layer  of  comparatively 
healthy  dentine.  The  slightest  pressure  upon  this  thin  layer  of 
dentine,  even  with  a  round  instrument,  will  yield  considerable 
pain.  In  these  instances,  therefore,  it  is  advisable  to  introduce 
into  the  cavity  of  the  tooth  a  small  piece  of  cotton,  upon  which 
slight  pressure  may  be  exerted  without  danger  of  injuring 
the  pulp.  When,  in  the  examination  of  a  tooth  affected  with 
partial  acute  pulpitis,  the  pulp  becomes  wounded,  bright-red 
blood  flows  from  the  pulp-chamber.  Percussion  will  sometimes 
elicit  a  sound  slightl}'  different  from  the  normal  in  a  tooth  af- 
fected with  partial  acute  pulpitis,  but  does  not  increase  the  pain 
during  a  paroxysm. 

Subjectire  Phenomena. — The  pains  produced  in  partial  acute 
inflammation  of  the  pulp  are  of  an  intermittent  character.  The 
attacks  last  from  five  minutes  to  an  hour,  but  during  the  intervals 
the  tooth  feels  comfortable,  though  slightly  sensitive  to  thermal 
changes,  especially  to  cold.  The  paroxysms  of  pain  mostly 
occur  once  or  twice  in  twenty -four  hours,  and  usually  not  until 
five  or  seven  o'clock  p.m.,  unless  during  mastication  food  has 
become  pressed  into  the  cavity  of  the  tooth.     When  the  tooth 

26 


386  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

has  been  subjected  to  extreme  thermal  changes  or  other  irritat- 
ing agents,  the  pain  is  often  quite  acute,  but  soon  ceases  upon 
the  removal  of  the  irritant.  In  this  form  of  pulpitis  the  patient 
usually  is  able  to  locate  the  pain  in  the  affected  tooth  ;  and  reflex 
phenomena  in  other  parts  of  the  nervous  system  rarely  accom- 
pany the  malady. 

Dijferential  Diagnosis. — Partial  acute  pulpitis  ma}^  be  con- 
founded with  total  acute  pulpitis,  but  in  the  latter  instance  the 
pulp  is  usually  exposed  largely  or  in  more  than  one  place.  If 
the  pulp-cavity  of  a  tooth  aft'ected  with  total  acute  pulpitis  be 
opened,  the  blood  oozing  forth  will  have  the  color  not  of  arterial 
but  of  venous  blood.  The  paroxysms  of  pain  are  more  frequent, 
and  last  longer  than  in  partial  pulpitis.  In  total  acute  pulpitis 
the  tooth  is  more  sensitive  to  hot  than  to  cold  substances;  per- 
cussion of  the  tooth  elicits  a  distinctly  dull  sound,  and  is  slightly 
painful. 

With  partial  acute  pulpitis,  gangrene  of  the  pulp  may  be  con- 
founded, as  the  subjective  symptoms  of  both  diseases  are  similar, 
although  in  gangrene  of  the  pulp  we  notice  a  characteristic  foetid 
odor  as  soon  as  the  pulp-chamber  is  opened. 

The  prof/nosis  in  partial  acute  pulpitis  is  usually  favorable  for 
the  preservation  of  the  pulp,  provided  the  inflammatory  process 
has  existed  onl}^  a  short  period,  and  has  only  extended  over  a 
small  area  of  the  pulp-tissue. 

b.  Total  Acute  Pulpitis. — Diagnosis. — In  this  form  of  pulpitis 
the  tooth  generally  is  much  decayed,  and  the  pulp  largely  ex- 
posed in  one  or  more  places.  Sometimes  we  find  the  pulp  not 
quite  exposed,  though  the  carious  cavity  is  large.  In  these 
instances,  if  a  total  acute  inflammation  be  present,  the  dentine 
between  the  pulp  and  the  carious  cavity  is  found  quite  soft  and 
thin.  If  the  carious  dentine  be  removed  from  the  cavity  and 
the  pulp-chamber  opened,  dark  venous  blood  flows  from  the 
pulp-chamber.  Percussion  upon  the  affected  tooth  alwaj's  elicits 
a  somewhat  dull  sound,  and  is  at  the  same  time  slightly  painful. 

Suhjectke  Symptoms. — The  pain  in  total  acute  pulpitis  is  inter- 
mittent but  severe,  the  paroxysms  lasting  from  one  to  six  hours 
at  a  time,  and  the  painless  intervals,  as  the  disease  progresses, 
becoming  shorter,  in  the  same  ratio  as  the  pain  during  the  par- 
oxysms is  increased.  Irritants,  or  pressure  into  the  carious 
cavity,  produce  severe  pain,  lasting  an  hour  or  more.  The  patient 
usually  complains  of  pain  on  the  whole  side  of  the  face,  and  is 


PULPITIS    IX    ITS    CLINICAL    ASPECTS.  387 

uuable  to  locate  it.  Often  reflex  phenomena  in  other  parts  of 
the  nervous  system  of  the  affected  side  are  present.  AVhen  one 
of  the  wisdom-teeth,  especially  a  lower  one,  becomes  affected 
with  total  acute  pulpitis,  reflex  pain  in  the  ear,  the  larynx,  the 
shoulder,  and  even  in  the  lungs  is  frequently  complained  of. 
In  the  latter  instance  the  patient  is  subject  to  great  difiiculty  in 
breathing.  If,  however,  the  affected  tooth  is  in  the  upper  jaw, 
the  reflex  pain  may  affect  the  nerves  of  the  supra-  and  infra- 
orbital region,  the  eye,  and  the  nose.  In  exceptional  cases  the 
pain  is  located  by  the  patient  in  teeth  of  the  opposite  jaw^, 
although  these  may  be  quite  sound.  Should  the  pulp  of  a  tooth 
affected  with  total  acute  pulpitis  be  left  without  treatment,  the 
pain  after  five  to  eight  days  becomes  less  acute,  and  the  inflam- 
matory process  gradually  assumes  a  chronic  character.  If  the 
carious  cavity  of  an  affected  second  or  third  mohir  tooth  is 
situated  in  one  of  the  approximal  surfaces,  it  sometimes  becomes 
difficult  to  tell  which  tooth  causes  the  ]3ain.  In  such  an  emer- 
gency either  percussion,  transillumination,  or  separation  by 
wedges  will  assist  the  practitioner  in  making  the  diagnosis. 
After  two  or  three  days  of  pain  from  total  acute  pulpitis,  the 
trouble  is  usually  localized  in  the  affected  tooth. 

Diferential  Diagnosis. — Total  acute  pulpitis  may  easily  be  con- 
founded wdth  other  diseases  of  the  pulp, — viz,  chronic  purulent 
pulpitis,  and  gangrene  of  the  pulp.  Chronic  purulent  pulpitis 
differs  from  total  acute  pulpitis  principally  in  its  reaction  upon 
the  pericementum.  In  the  former  disease  the  tooth  becomes 
quite  sensitive  to  pressure  and  percussion  after  the  first  day  of 
inflammation,  whereas  in  the  latter  the  apparent  elongation  of 
the  tooth  and  its  sensitiveness  to  percussion  and  pressure  are  not 
marked  in  so  high  a  degree,  and  do  not  appear  till  the  third  or 
fourth  day  after  the  beginning  of  the  total  acute  pulpitis. 

The  subjective  and  objective  phenomena  of  gangrene  of  the 
pulp  are  quite  similar  to  those  of  total  acute  pulpitis.  We  are, 
therefore,  unable  to  differentiate  between  these  two  diseases. 

Prognosis. — It  is  not  advisable  to  attempt  to  save  a  pulp  that 
has  become  the  seat  of  total  inflammation.  The  only  way  to 
preserve  the  tooth  permanently  is  completely  to  extirpate  the 
pulp,  and  thoroughly  to  disinfect  and  fill  the  pulp-canal.  When 
this  has  been  successfully  accomplished,  the  tooth  may  last  as 
long  as  though  it  had  a  living  pulp. 

2.  Acute  Purulent  Pulpitis.— The  pathological  description  of 


388  THE    ANATOMY    AND    PATHOLOUY    OF    THE    TEETH. 

this  disease  is  divided  under  the  heads  of  'partial  and  total  pul- 
pitis. Clinically,  however,  a  dift'erentiation  is  neither  possible 
nor  important.  I  shall  therefore  describe  acute  purulent  pid- 
pitis  under  one  head. 

Diagnosis. — When  the  carious  dentine  is  careful!}'-  removed 
from  the  cavity  of  a  tooth  aiiected  with  acute  purulent  pulpitis, 
we  always  find  the  pulp  exposed,  at  least  at  one  of  its  horns. 
The  exposed  portion  of  the  pulp  does  not  lie  close  up  to  the  den- 
tinal wall  of  the  pulp-chamber,  but  recedes  somewhat  from  it 
at  the  orifice.  As  soon  as  the  pulp-chamber  is  opened,  pus  oozes 
out,  whereupon  the  patient  is  instantly  relieved  from  }  >ain.  Pres- 
sure through  a  piece  of  cotton  or  a  blunt  instrument  upon  the 
exposed  portion  of  the  pulp,  before  the  pulp-chamber  has  been 
opened,  does  not  increase  the  pain  instantly,  but  after  a  few 
seconds;  and  if  then  the  pus  be  allowed  to  escape,  the  pain 
ceases  altogether.  Percussion  upon  a  tooth  affected  with  in- 
cipient acute  purulent  pulpitis  produces  no  pain,  although  its 
sound  may  be  slightly  dull.  After  the  second  or  third  day  the 
tooth  will  be  sensitive  to  percussion,  and  its  sound  will  be  dis- 
tinctly dull. 

Subjective  Phenomena. — In  acute  purulent  pulpitis  the  pain  is 
pulsatory,  but  seldom  as  severe  as  in  the  foregoing  forms  of 
pulpitis.  The  paroxysms  of  pain  are  protracted,  usually  from 
four  to  twelve  liours,  and  as  the  disease  proceeds  the  painless 
intervals  are  progressively  shortened,  until  the  pain  becomes 
continuous.  In  those  cases  where  thepul]>  is  still  covered  with 
a  layer  of  softened  dentine,  the  tooth  is  extremely  sensitive  to 
heat,  but  the  pain  is  relieved  upon  the  application  of  cold.  The 
pain  in  the  affected  tooth  produced  by  the  heat  is  due  1o  the 
expansion  of  gases  accompanying  the  pus  in  the  closed  pulp- 
chamber.  As  gases  are  greatly  expanded  by  heat,  the  result  is 
obvious.  In  some  instances,  and  especially  in  weakly-constituted 
persons,  acute  purulent  pulpitis  is  accompanied  by  an  elevation 
in  the  temperature  of  the  patient,  which  begins  as  soon  as  jius 
forms. 

Differential  Diagnosis. — Acute  purulent  pulpitis  may  be  con- 
founded with  three  other  diseases  of  the  pulp, — viz,  loartial  acute 
-pulpitis,  chronic  purulent  pulpitis,  and  gangrene  of  the  piclp.  In 
partial  acute  pulpitis  the  pain  is  more  intermittent,  and  when 
the  carious  portion  is  lemoved  from  the  cavity  of  the  afiected 
tooth,  the  pulp  almost  protrudes,  and  if  wounded  will   viekl 


PULPITIS    IN    ITS    CLINICAL    ASPECTS.  389 

briglit-red  blood ;  while  in  acute  purulent  pulpitis  the  pulp  is 
somewhat  retracted  at  the  exposed  horn,  is  very  sensitive  to 
heat,  and  when  the  pulp-chamber  is  opened  pus  instead  of 
blood  oozes  out.  The  principal  difierence  between  acute  and 
chronic  purulent  pulpitis  is  tliat  in  the  latter  the  pulp  is  exposed 
quite  largely,  or  in  several  places,  the  pain  is  much  less  severe, 
and  the  tooth  aches  but  little  upon  application  of  heat.  Gan- 
grene of  the  pulp  also  may  be  mistaken  for  acute  purulent  pul- 
pitis, but  when  the  pulp-chamber  of  a  tooth  aifected  with  the 
former  disease  is  opened  we  observe  in  it  a  grayish  or  brownish 
fluid,  with  the  characteristic  odor  of  gangrene. 

The  prognosis  for  pulps  of  teeth  affected  with  acute  purulent 
pulpitis  is  always  unfavorable.  In  these  instances  the  sooner 
the  pulp  is  removed,  and  the  pulp-canal  disinfected  and  filled, 
the  better.  This,  successfully  accomplished,  will  usually  save 
the  tooth. 

III.    CHRONIC  PULPITIS. 

1.  Hyperplasia. — a.  Paktial. — Clinically  considered,  there  are 
two  varieties  of  partially  hyperplastic  pulps, — the  myxofibrous 
and  the  sarcomatous.  But  as  the  latter  belongs  to  the  tumors, 
I  shall  consider  it  in  the  chapter  on  that  subject. 

Diagnosis. — Under  the  head  of  partial  hyperplasia  we  will 
consider  such  pulps  as  are  found  in  teeth  largely  decayed  in 
their  entire  grinding-surface,  and  exposed  at  one  or  all  of  their 
horns.  The  pulps  have  grown  out  of  the  pulp-chamber,  and 
their  surface  presents  a  lobulated  appearance,  of  a  crimson  hue. 
These  little  tumors  of  the  pulp  vary  in  size  from  that  of  the 
head  of  a  pin  to  that  of  a  pea,  or  even  more.  They  occur 
mostly  in  the  molar  teeth;  sonietimes  they  are  seen  in  the 
bicuspids  and  cuspids,  exceptionally  in  the  incisors.  This  dis- 
ease, when  it  aifects  the  pulp  of  an  upper  molar,  starts  usually 
from  the  lingual  root,  while  hyperplasia  of  the  lower  molars 
commonly  originates  in  both  roots.  Pulps  affected  with  par- 
tial hyperplasia  are  not  very  sensitive  to  mastication,  nor  to  the 
touch  of  an  instrument.  Even  a  probe  introduced  along  the 
wall  of  the  pulp-chamber  for  a  little  distance  produces  no  pain, 
though  it  will  usually  start  a  profuse  hemorrhage.  The  hyper- 
plastic portion  is  connected  with  the  unchanged  pulp  within 
the  pulp-chamber  or  the  canals  by  means  of  a  constricted  stem 
or  pedicle. 


390  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

The  subjective  jphenomena  of  partial  hyperplasia  are  quite  few, 
and  beyond  a  sensation  of  uneasiness  in  the  affected  teeth  no 
pain  exists,  unless  pronounced  thermal  changes  or  mechanical 
injury  affect  the  pulp. 

Differential  Diagnosis. — Partial  hyperplasia  of  the  pulps  may 
sometimes  be  confounded  with  granuloma  of  the  gums,  or  the 
pericementum  which  occasionally  occurs  when,  besides  the 
cavity  in  the  grinding-surface,  a  tooth  also  contains  a  carious 
cavity  in  the  neck  under  the  gum  communicating  with  the 
pulp-chamber.  In  these  cases  the  gum  or  the  pericementum 
may  grow  into  the  pulp-chamber  and  appear  in  the  cavity  on 
the  grinding-surface  of  the  tooth.  Their  vulnerability  renders 
an  examination  difficult,  and  the  best  way  to  arrive  at  a  correct 
diagnosis  is  to  insert  a  piece  of  cotton  saturated  with  carbolic 
acid  as  far  into  the  pulp-chamber  as  possible,  leaving  it  for  about 
twenty-four  hours.  Then  we  are  usually  able  to  make  the 
examination. 

The  prognosis  for  the  preservation  of  the  pulp  is  bad;  but  the 
tooth  can  be  saved  if  the  pulp  be  extirpated  and  the  canals 
filled,  which  in  partial  hyperplastic  conditions  of  the  pulp  is 
usually  easy  to  accomplish. 

h.  Total  Hyperplasia. — Diagnosis. — This  disease  is  more 
common  in  teeth  whose  pulps  are  largely  exposed  by  caries, 
but  is  met  with  in  some  instances,  where  the  pulp  is  still  covered 
by  softened  dentine.  Pressure  upon  the  dentine  in  the  vicinity 
of  the  pulp  is  not  painful,  except  when  foreign  substances  enter 
the  pulp-chamber.  When  the  softened  dentine  is  removed  from 
the  carious  cavity,  and  the  pulp  exposed,  we  are  able  to  enter  it 
for  some  distance  with  a  fine  instrument,  and  sometimes  we 
even  touch  the  periphery  of  the  pulp  without  producing  pain. 
But  the  pulp  in  this  condition  bleeds  easily  and  profusely  upon 
the  slightest  injury.  The  tooth  is  acutely  sensitive  to  thermal 
changes,  and  an  injection  of  hot  or  cold  water  into  the  cavity 
causes  pain.  The  pain,  however,  does  not  start  of  a  sudden, 
but  gradually,  lasting  from  one  to  ten  minutes.  As  a  rule,  the 
tooth  is  somewhat  loose,  though  not  sensitive  under  pressure 
nor  during  mastication  unless  these  irritate  the  pulp  directly. 
Percussion  upon  the  afi:ected  tooth  is  answered  with  a  slight 
dullness  in  the  sound,  and  also  detects  a  tenderness,  which  proves 
that  the  chronic  inflammation  of  the  pulp  has  reacted  upon  the 
pericementum. 


PULPITIS    IX    ITS    CLINICAL    ASPECTS.  391 

Subjective  Phenomena. — In  chronic  hyperplasia  of  the  pulps  we 
rarely  observe  severe  pain,  unless  the  inflammatory  process 
should  enter  an  acute  stage.  The  first  warning  the  patient  has 
of  the  trouble  consists  of  an  uneasy  sensation,  which  he  is 
usually  able  to  localize  in  the  atfected  tooth.  This  may  continue 
from  fifteen  minutes  to  three  or  four  hours,  followed  by  abso- 
lutely painless  intervals  of  a  day,  a  week,  or  even  of  months. 
The  paroxysms  of  pain  are  usually  produced  h\  irritating  sub- 
stances brought  in  contact  with  the  exposed  pulp,  although 
in  some  cases  constitutional  derangements  are  apt  to  bring  on  a 
paroxysm  of  pain,  oftentimes  acute.  Whenever  the  pulp  of 
such  a  tooth  becomes  disturbed,  either  by  constitutional  or  local 
irritants,  the  tooth  begins  to  ache  severely  and  exhibits  all  the 
phenomena  of  a  total  acute  pulpitis,  lasting  from  two  to  four 
days.  "When  the  patient  suffers  from  such  an  acute  attack,  we 
usually  observe  reflex  pains  in  other  parts  of  the  nervous  system, 
similar  to  those  experienced  in  total  acute  pulpitis,  when  pro- 
duced by  eburnification  and  ossification  of  the  pulp.  Usually 
after  that  the  tooth  is  comfortable  for  several  weeks  or  months. 
Ever}'  attempt  at  destroying,  by  means  of  arsenious  acid,  a  pulp 
.affected  with  total  hyperplasia  will  result  in  an  excruciatingly 
painful  paroxysm,  and  in  a  failure  to  accomplish  devitalization. 
The  character  of  the  pain  in  such  an  acute  paroxysm  is  mostly 
dependent  upon  the  area  of  the  exposure  of  the  pulp.  In  cases 
where  the  pulp  is  largely  exposed  and  not  covered  by  softened 
dentine,  the  pain  will  be  considerably  less  than  in  cases  where 
the  exposure  of  the  pulp  is  small,  or  the  pulp  is  still  covered  by 
softened  dentine. 

Differential  Diagnosis. — Three  diseases  of  the  pulp  maybe  con- 
founded with  total  hyperplasia  of  the  pulp  :  total  acute  pulpitis, 
gangrene  of  the  pulp,  eburnification  and  ossification  of  the  pulp. 
The  principal  difierence  between  total  acute  pulpitis  and  total 
hyperplasia  of  the  pulp  is  in  the  reaction  produced  upon  the 
pericementum,  which  in  the  former  instance  is  but  slight;  in 
the  latter,  quite  noticeable.  Another  characteristic  feature  of 
hyperplastic  pulps  is  their  behavior  upon  the  application  of 
carbolic  acid,  campho-phenique,phenate  of  cocaine,  aconite,  etc., 
which  in  this  disease  never  give  ready  relief  when  applied 
during  an  acute  paroxysm  of  pain,  whereas  they  act  instantly 
in  cases  of  total  acute  pulpitis;.  Gangrene  of  the  pulp  can  be 
distinguished  from  its  total  hyperplasia,  although  the  subjective 


392  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

and  the  objective  symptoms  of  both  diseases  are  similar.  In  the 
former,  when  the  pnlp-chamber  is  opened  we  olserve  the  char- 
acteristic smell  of  gangrene,  which  never  is  present  in  total 
hyperplasia  of  the  pulp.  Quite  different,  however,  is  the  case 
when  the  tooth  is  so  sensitive  that  we  are  unable  to  open  the 
pnlp-chamber.  In  such  an  instance  a  correct  ditferentiation 
between  these  two  diseases  cannot  be  made.  Total  h^-perplasia 
of  the  pulp  may  also  be  confounded  with  eburnilication  and 
ossification  of  the  pulp,  the  more  so  as  most  of  the  liyperj>lastic 
pulps  in  time  partially  degenerate  into  dentine  and  bone.  More- 
over, the  degeneration  into  dentine  and  bone,  as  spoken  of  in 
the  next  chapter,  principal!}'  occurs  in  teeth  not  aifected  by 
caries.  Whether  this  exists  or  not  can  be  ascertained  by  careful 
examination. 

2.  Chronic  Purulent  Pulpitis.— The  morbid  anatomy  of 
chronic  purulent  pulpitis,  like  that  of  acute  purulent  pulpitis, 
admits  of  two  forms  of  the  disease  under  consideration.  As 
it  is  of  little  importance  to  the  practitioner  whether  a  pulp  is 
affected  by  partial,  or  by  total  chronic  purulent  pulpitis,  I  shall 
discuss  the  disease  in  one  yiaragraph,  especially  since  the 
term  total  puruleiit  pulpitis,  as  usually  applied,  is  a  misnomer. 
So  soon  as  all  the  pulp-tissue  has  been  transformed  into  pus, 
there  is  no  longer  miy  pulpitis,  but  a  pulp-chamber  tilled  with 
pus  instead.  In  the  majority  of  instances,  however,  we  still 
find  rerimants  of  pulp-tissue,  as  evidenced  in  the  chapter  on  ihe 
morbid  anatom}'  of  pulpitis. 

Diagnosis. — Chronic  purulent  pulpitis  is  found  in  teeth  with 
large  carious  cavities,  whereby  the  pulp  has  been  exposed  largely 
or  in  several  places.  The  dentine  covering  the  exposed  portions 
of  the  pulp  is  always  quite  soft,  and  frequently  such  a  deteriora- 
tion extends  over  the  greater  portion  of  the  pulp-chamber. 
This  form  of  pulpitis  is  easih^  recognizable  by  the  quantity  of 
pus  eliminated  upon  the  opening  of  the  pulp-chamber,  in  cases 
where  this  has  remained  covered  b}^  softened  dentine.  Usually 
but  a  few  drops  of  pus  appear,  but  in  exceptional  cases  the  pulp- 
chamber,  on  being  opened,  yields  about  a  teaspoonful  of  pus  or 
even  more.  In  such  instances  there  is  present,  additionally  to 
the  pulpitis  under  consideration,  an  acute  or  chronic  purulent 
pericementitis.  In  general,  however,  in  this  disease,  when  the 
pulp-chamber  is  found  open,  most  of  the  pus  has  already 
escaped,  and  upon  examination  we  only  find  one  or  two  drops 


PULPITIS    IX    ITS    CLINICAL    ASPECTS.  393 

of  it  iu  the  piilp-chamber.  A  probe  may  be  introduced  into  the 
pulp-chamber  for  some  distance  without  producing  either  pain 
or  hemorrhage.  Indeed,  when  an  instrument  enters  the  pulp- 
chamber  of  the  tooth,  causing  the  evacuation  of  the  pus,  the 
patient  is  instantly  relieA^ed.  Pressure  upon  the  softened  dentine 
in  the  vicinity  of  the  pulp-chamber  elicits  no  reaction,  except  in 
those  rare  cases  where  the  pulp-chamber  is  still  inclosed  by  soft- 
ened dentine.  A  characteristic  feature  of  this  form  of  pulpitis 
is  the  presence  of  pericementitis,  which  in  the  earlier  stages  of 
chronic  purulent  pulpitis  is  acute.  In  those  instances,  on  the 
contrary,  in  which  the  pulp-chamber  has  been  largely  perforated, 
and  chronic  purulent  pulpitis  has  existed  for  four  weeks  or  more, 
it  is  associated  with  chronic  purulent  pericementitis.  Percus- 
sion as  well  as  slight  pressure  upon  the  affected  tooth  will  be 
quite  painful,  and  the  former  will  elicit  the  characteristic  dull 
sound. 

Subjective  Phenomena. — In  chronic  purulent  pulpitis,  the  patient 
complains  of  moderate  throbbing  and  shooting  pain  in  the 
affected  tooth,  which,  owing  to  the  inflammatory  process  set 
up  in  the  pericementum,  is  quite  sensitive  upon  mastication. 
"When  the  perforation  in  the  pulp-chamber  is  small,  and  most 
or  all  of  the  pus  ■  retained  in  the  pulp-chamber,  the  tooth  is 
extremely  sensitive  to  heat,  which,  however,  is  not  the  case 
when  the  perforation  of  the  pulp-chamber  permits  the  evacua- 
tion of  the  pus.  Usually,  whenever  pus  is  form-ed,  the  patient 
is  attacked  by  a  chill  followed  by  more  or  less  fever,  the  severity 
of  which  depends  upon  the  quantity  of  pus  accumulated  in  the 
pulp-chamber  and  the  pericementum,  as  well  as  upon  the  con- 
stitutional peculiarities  of  the  patient. 

Differential  Diagnosis. — Chronic  purulent  pulpitis  may  be  con- 
founded with  four  diseases, — viz,  acute  jnirulent  pulpitis,  acute 
total  pulpitis,  gangrene  of  the  pulp,  and  acute  alveolar  abscess. 
Acute  purulent  pulpitis  differs  from  the  chronic  form  principally 
in  the  inflammatory  reaction  which  the  latter  always  produces, 
while  in  the  former  it  is  scarcely  noticeable.  Other  character- 
istic features  of  chronic  purulent  pulpitis  are  the  large  extent  of 
the  carious  cavities,  and  the  quantity  of  pus  eliminated  upon 
opening  the  pulp-chamber;  whereas  in  acute  purulent  pulpitis 
the  pulp  is,  as  a  rule,  exposed  only  at  one  of  its  horns,  and  but 
one  or  two  drops  of  pus  are  seen  at  the  perforation  of  the  pulp- 
chamber.     Total  acute   pulpitis  differs  from  chronic  purulent 


394  THE    ANATOMY   AND    PATHOLOGY.  OF    THE    TEETH. 

pulpitis  principally  in  that  when  the  pulp-chamber  is  opened 
blood  oozes  forth,  and  pressure  in  the  vicinity  of  the  pulp- 
chamber  produces  intense  pain ;  whereas  in  chronic  purulent 
pulpitis  pus  is  present,  and  no  pain  is  experienced  upon  pressure 
in  the  neighborhood  of  the  pulp-chamber.  In  its  latter  stages 
chronic  purulent  pulpitis  may  easily  be  confounded  with  acute 
alveolar  abscess,  while  in  its  beginning  we  always  find  traces 
of  sensitive  pulp-tissue  in  some  parts  of  the  pulp-chamber  or 
root-canal. 

Prognosis. — In  chronic  purulent  pulpitis  the  death  of  the  pulp 
of  the  tooth  is  inevitable,  and  the  earlier  the  pulp  be  extirpated 
the  better  is  the  chance  of  preventing  the  formation  of  an  acute 
alveolar  abscess.  When  pericementitis  has  but  slightly  developed, 
and  great  care  is  exercised  in  the  removal  of  the  pulp,  by  absolutely 
aseptic  instruments,  tlie  canals  after  a  thorough  preparation  and 
disinfection  may  at  once  be  filled  and  no  trouble  will  follow,  pro- 
vided micro-organisms  have  not  already  entered  the  pericemen- 
tum during  the  process  of  pulpitis.  If,  however,  the  pericemen- 
titis has  progressed  to  the  stage  of  tenderness  or  fluctuation 
above  the  end  of  the  root,  the  pulp-canal  cannot  be  tilled  at  once,, 
though  by  skillful  treatment  the  preservation  of  the  tooth  is 
possible. 

IV.    GANGRENE  OF  THE  PULP. 

a.  Moist. — This  disease  is  most  common  in  carious  teeth,  the 
pulp-cliambers  of  which  are  still  covered  with  softened  dentine. 
The  extent  of  the  carious  cavities  in  the  teeth  afl:ected  with 
moist  gangrene  seems  to  have  no  influence  upon  the  infection  of 
the  pulp.  In  some  instances  we  meet  with  carious  cavities 
representing  an  almost  straight  tube-like  canal,  not  much  larger 
in  diameter  than  a  stout  nerve-broach  ;  in  others  we  see  almost 
the  whole  crown  of  the  tooth  lost,  betore  the  pulp  is  attacked 
by  moist  gangrene.  This  process  usuall}'  starts  at  one  of  the 
horns  of  the  pulp,  rapidly  destroying  it  in  the  direction  of  the 
root.  For  this  reason  an  examination  by  means  of  a  probe,, 
when  handled  carefully,  is  painless  to  the  patient,  even  in  the 
first  stages  of  moist  gangrene.  At  the  same  time  the  examina- 
tion of  the  pulp-chamber  of  such  a  tooth  will  leave  no  doubt  as 
to  the  correctness  of  the  diagnosis,  because  the  instrument  em- 
ployed will  inevitably  be  tainted  with  the  characteristic  odor 
of  gangrene.     In  perforating  the  pulp-chamber  of  a  tooth,  the 


PULPITIS    IX    ITS    CLINICAL    ASPECTS.  395 

pulp  of  which  we  susj^ect  to  be  gangrenous,  care  must  be  exer- 
cised not  to  exert  too  much  pressure,  as  in  the  beginning  of  the 
process  only  the  horn  is  destroved,  and  the  instrument  might 
enter  the  vet  unaifected  pulp-tissue,  an  exceedingly  painful  acci- 
dent. In  many  instances,  howeyer,  we  are  enabled  to  pass  the 
broach  almost  to  the  apex  of  the  root  without  producing  pain. 
In  these  cases,  when  an  infection  of  the  pericementum  has 
occurred,  the  gangrenous  process  has  adyanced  nearly  to  the 
apex  of  the  root;  or  it  will  do  so  as  soon  as  a  broach  reaches  the 
apical  foramen  of  the  roots  of  the  tooth,  unless  the  pulp-canal 
had  been  pre^■iously  made  aseptic.  It  is  therefore  adyisable 
during  the  examination  of  a  pulp-canal  never  to  enter  the  root- 
canals  of  a  tooth  by  instruments.  One  of  the  most  characteristic 
signs  of  both  moist  and  dry  gangrene  is  the  discoloration  of  the 
tooth,  especially  marked  in  the  incisors  and  cuspids.  Before 
other  instruments  are  employed,  transillumination,  either  by 
reflected  or  electric  light,  will  greatly  assist  in  making  the  diag- 
nosis. The  color  of  such  teeth  depends  upon  the  acuteness 
and  the  stage  of  the  process.  At  the  beginning  of  gangrene, 
when  only  a  part  of  the  coronal  portion  of  the  pulp  has  been 
destroyed,  there  is  seldom  any  discoloration  yisible.  In  further 
stages,  howeyer,  when  most  of  the  coronal  portion  of  the  pulp 
has  been  deyitalized,  the  tooth  changes  its  color,  at  flrst  to  a 
slightly  grayish-blue,  gradually  becoming  darker,  until  it  assumes 
a  dirty  brownish  or  eyen  blackish  shade.  In  some  instances, 
when  in  the  process  of  acute  pulpitis  a  blood-yessel  had  rup- 
tured, and  the  pulp  dies,  the  tooth  rapidly  changes  its  color,  at 
first  to  a  light  pink,  and  after  one  or  two  weeks  to  a  dark  brown. 
The  discoloration  in  all  instances,  howeyer,  will  be  slight,  or 
eyen  not  noticeable  at  all,  when  the  pulp  has  been  remoyed  before 
it  is  wholly  destroyed  by  the  gangrenous  process. 

The  subjective  phenomena  of  moist  gangrene  are  quite  seyere 
intermittent  pains,  which  in  the  first  stages  last  from  a  few 
minutes  to  half  an  hour.  In  the  later  stages,  howeyer,  a  parox- 
ysm may  last  oyer  one  hour.  The  pain  mostly  arises  spon- 
taneously, and  does  not  seem  to  be  started  nor  aggrayated  by 
thermal  changes.  A  tooth  aflected  with  moist  gangrene  is 
neyer  quite  free  from  pain,  Eyen  between  the  paroxysms  the 
patient  complains  of  an  uneasy  feeling  or  slight  pain,  that 
increases  in  seyerity  as  the  gangrene  adyances.  In  the  latter 
stages  of  the  process  the  tooth,  up  to  that  time  comfortable. 


396  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

begins  to  get  sore  in  mastication,  and  becomes  elongated  in  its 
socket, — a  characteristic  sign  of  the  infection  of  the  peri- 
cementum and  its  inflammation. 

Diferevtuil  Diagnosis. — Moist  gangrene  of  the  pulp  may  be 
confounded  with  the  majority  of  the  diseases  of  the  pulp,  but 
especially  with  acute  ■partial,  acute  total,  acute  purulent,  and  chronic 
purideiU  jm.lpitis.  The  principal  characteristic  symptoms  of  gan- 
grene of  the  pulp  are  usually  a  sensitiveness  to  pressure  upon 
the  softened  dentine  of  the  pulp,  and,  when  the  instrument 
enters  the  pulp-chamber,  the  gangrenous  odor. 

Prognosis. — In  the  first  stages  of  moist  gangrene  of  the  pulp 
we  may,  in  some  instances,  succeed  in  amputating  the  coronal 
portion  of  the  pulp,  and  thus  save  the  pulp-stumps;  but  this 
success  must  be  regarded  as  exceptional.  The  best  procedure 
to  preserve  the  tooth  is  the  complete  extirpation  of  the  pulp  and 
filling  of  the  root-canals  as  soon  as  the  diagnosis  of  gangrene  of 
the  pulp  has  been  made.  The  earlier  this  is  accomplished  the 
better  will  be  the  color  of  the  tooth,  and  the  less  is  the  probability 
of  a  succeeding  pericementitis. 

b.  Dry  Gangrene. — Diagnosis. — While  moist  gangrene  is  of 
frequent  occurrence,  dry  gangrene  of  the  pulp  is  not  so  often 
observed.  Dry  gangrene  of  the  pulp  usually  occurs  in  teeth  the 
crowns  of  which  have  not  been  attacked  by  deep-seated  caries. 
The  teeth  usually  show  a  grayish-blue  discoloration,  and  often 
this  has  been  noticed  for  years  before  such  teeth  have  given  pain 
or  discomfort.  Percussion  upon  a  tooth  affected  with  dry  gan- 
grene will  produce  no  pain,  but  often  a  slightly  dull  sound. 

Subjectioe  Phenomena. — Besides  the  discoloration  of  the  tooth, 
there  is  no  symptom  to  inform  the  patient  of  the  existence  of 
the  disease. 

Differential  Diagnosis. — Dry  gangrene  may,  perhaps,  be  con- 
founded with  moist  gangrene  of  the  pulp,  although  in  the  latter 
disease  the  patient  has  suffered  more  or  less  pain  before  the 
tooth  became  discolored,  and  when  the  pulp-chamber  is  opened 
the  characteristic  smell  is  present.  Teeth  affected  by  dry  gan- 
grene are  not  decayed,  and  when  the  pulp-cha'rnber  is  opened 
we  find  a  grayish-white  filamentous  substance,  perfectly  dry,  and 
with  no  perceptible  odor.  Some  teeth  affected  with  dry  gan- 
grene remain  so  perfect  in  color  that  a  differentiation  between 
them  and  the  teeth  with  living  pulps  is  almost  impossible.  In 
such  instances  an  application  of  the  chloride-of-methyl  spray 


MORBID    ANATOMY    OF    PULPITIS.  397 

ought  to  be  made  as  near  to  the  neck  of  the  tooth  as  possible, 
with  the  precaution  to  adjust  the  rubber-clam  on  the  tooth  to  be 
sprayed.  If  the  tooth  does  not  react  upon  the  spray,  the  pulp 
is  dead;  whereas  a  living  pulp  will. ache  considerably  upon  the 
use  of  the  chloride-of-methyl  spray. 

The  prognosis  of  a  tooth  affected  with  dry  gangrene  is  always 
favorable,  and  when  the  tooth  is  bleached  by  pyrozone,  the  dis- 
coloration usually  does  not  return. 


CHAPTER  XXXV. 

MORBID  ANATOMY  OF  PULPITIS. 


I.  Acute  Pulpitis. — In  accordance  with  the  classification  of 
pulpitis  laid  down  in  the  previous  chapter,  I  propose  to  consider 
first  the  acute  non-purulent  form. 

a.  Acute  Non-Purulent  Pulpitis. — This  may  be  either  partial  or 
total,  the  former  being  far  more  common  than  the  latter. 
Partial  pulpitis  is  usually  found  in  the  crown  portion,  starting 
from  its  surface  and  due  to  an  irritation  brought  to  bear  upon 
the  pulp-tissue,  commonly  by  the  approach  of  a  carious  process. 
It  is  much  less  frequenth"  met  with  in  the  root-portion  of  the 
pulp,  having  for  its  origin  an  irritation  transferred  from  peri- 
cementitis. 

Acute  superficial  pulpitis  is  illustrated  with  a  low  power  in 
Fig.  210.  In  this  example  only  the  surface  of  one  horn  of  the 
crown  portion  has  been  attacked.  We  may  infer  that  this  same 
horn  had  been  previously  attacked  by  a  slight  plastic  inflam- 
mation which  led  to  fibrous  hyperplasia,  and  a  deposition  of 
lime-salts  in  the  shape  of  osteoid  tissue  (0).  The  later  acute 
attack  has,  however,  led  to  an  acute  inflammation  even  of  the 
fibrous  portion.  A  peculiar  feature  observable  in  this  pulp,  and 
one  with  which  we  frequentl}^  meet  in  pulpitis,  is  the  general 
dissemination  of  the  inflammatory  foci  (i^),  which  are-  usually 
established  around  larger  blood-vessels. 

Specimens  of  this  type,  if  carefully  preserved  in  dilute  chromic- 
acid  solution  and  sliced  by  the  microtome,  aftbrd  excellent 
opportunity  for  the  study  of  the  process  of  pulpitis,  with  medium 


398 


THE    ANATOMY   AND    PATHOLOaY    OF    THE    TEETH. 


and  high  powers  of  the  microscope,  (See  Fig.  211.)  The  spot 
selected  for  illustration  exhibits  three  grades  of  acute  pulpitis, 
passing  from  a  quite  intensely-inflamed  region  to   a  slightly- 


FiG.  210. 


Acute  Pulpitis  ix  the  Coeoxal  Portion. 

/.intensely-inflamed  horn;    0,  osteoid  tissue;  i^,  apparently  isolated  inflammatory  focus. 
Magnified  10  diameters. 

inflamed  one.  In  the  former,  the  myxomatous  structure  of  the 
pulp-tissue  is  nearly  destroyed,  and  in  its  stead  we  see  a  large 
number  of  lumps  of  living  matter,  mostly  clustered,  in  varying 


MORBID    AXATOMY    OF    PULPITIS. 


399 


phases  of  development,  from  a  minute  granule  of  compact 
living  matter  to  a  distinctly  outlined,  coarsely-granular  proto- 
plasmic body.  We  trace  the  development  of  such  lumps,  not 
only  from  previous  lymph-corpuscles  by  a  process  of  splitting  or 


Tig.  211. 


Acute  Pulpitis. 

1,  intensely-inflamed  portion  ;  M,  moderately-inflamed  portion  ;  S,  slightly-inflamed  portion  ; 
JV,  N,  small  bundles  of  medullated  nerves,  intensely  inflamed ;  B,  large  bundle  of  medullated 
nerves,  slightly  inflamed  ;  T,  nerve-bundle  in  transverse  section  ;  T",  vein,  engorged  with  red 
and  colorless  blood-corpuscles  ;  C,  capillary,  engorged  and  widened.    Magnified  500  diameters. 


division,  but  also  from  the  trabeculfe  of  the  myxomatous  net- 
work and  from  the  protoplasm  or  myxomatous  substance  filling 
the  meshes  of  the  myxomatous  net-work.  Since  the  develop- 
ment of  these  so-called  inflammatory  corpuscles   is  so   easily 


400 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


traceable,  as  originating  from  all  the  components  of  tlie  pulp- 
tissue,  we  again  are  placed  in  position  to  emphatically  deny  the 
emigration  of  leucocytes  according  to  J.  Cohnheim's  theory. 
True  it  is  that  the  capillaries  and  small  veins  within  the  inflam- 
matory focus  are  engorged  with  red  and  colorless  blood-corpus- 
cles, the  latter  being  accumulated  mainly  along  the  walls  of  the 
vessels.  True  it  is,  also,  that  the  leucocytes  creep  through  the 
walls  of  the  capillaries  and  small  veins ;  but  this  occurs  in  the 
preliminary  stage  of  inflammation  in  hypersemia,  and  is  by  no 
means  an  essential  feature  of  inflammation. 


Fig.  212. 


-  —  J/ 


Acute  Pulpitis. 

6'.  secondary  dentine  ;  B,  bay-like  excavations  filled  with  medullary  or  inflammatory  corpus- 
cles :  F,  transverse  section  of  a  bkod -vessel;  J/,  multinuelear  body.     Magnified  300  diameters. 

The  nerve-bundles  break  up  into  inflammatory  corpuscles. 
First  the  perineurium,  next  the  myelin  investment,  then  after  the 
disappearance  of  the  myelin,  lastly  the  axis-cylinders  themselves 
take  part  in  the  production  of  inflammatory  corpuscles.  This 
transformation  easily  explains  the  severe  pains  caused  by  an  acute 
though  only  superficial  pulpitis. 

Should  an  acute  inflammation  start  in  a  pulp  around  which 
secondary  dentine  had  been  formed,  the  latter  would  likewise 
be  afiected,  its  lime-salts  being  dissolved  out  in  bays  similar  to 


MORBID    ANATOMY    OF    PULPITIS.  401 

those  seen  in  inflamed  cementum  and  bone-tissue,  filled  with 
multinuclear  protoplasmic  bodies  or  inflammatory  corpuscles. 
(See  Fig.  212.) 

There  are  two  ways  of  explaining  this  feature, — i.e.,  the 
inflamed  tissue  itself  may  have  caused  the  liquefaction  of  the 
basis-substance  of  the  secondary  dentine  and  grown  into  the 
bays  thus  produced;  or  the  living  matter  belonging  to  the  sec- 
ondary dentine  may  have  grown  up  to  inflammatory  corpuscles 
and  so-called  o-iant-cells.  The  latter  view  seems  to  me  to  be  the 
most  probable. 

All  the  tissue-changes  described  become  less  pronounced  the 
nearer  we  approach  the  healthy  portion  of  the  pulp,  and  frequently 
the  border-line  between  the  inflamed  and  normal  portion  is 
quite  abrupt. 

Among  recent  authors,  Arkovy  and  Rothmann  describe  a 
septic  superficial  pulpitis  due  to  an  invasion  of  the  pulp  by 
streptococci.  Rothmann  depicts  this  alleged  form  of  pulpitis; 
but  in  his  figure  only  normal  pulp-tissue  is  seen,  together  with 
a  few  streptococci.  Whether  or  not  such  a  partial  septic  pulpitis 
exists  I  am  unable  to  say  from  my  own  observation,  and  I  fully 
concur  with  A.  Witzel  in  the  view  that  in  such  cases  we  have 
no  right  to  speak  of  pulpitis,  but  only  of  irritation  of  the  pulp. 

Should  the  entire  pulp  be  affected,  which  is  very  rare,  it  will 
be  found  crowded  with  inflammatory  corpuscles.  The  outcome 
of  this  form  of  pulpitis  seems  to  be  invariably  suppuration,  or, 
through  the  complete  destruction  of  all  blood-vessels,  gangrene 
of  the  pulp. 

b.  Purulent  Pulpitis. — So  long  as  the  inflammatory  corpuscles 
remain  interconnected,  inflammation  of  the  pulp  is  always  non- 
purulent. So  soon,  on  the  contrary,  as  the  connections  of  the 
corpuscles  are  torn,  we  have  as  a  result  the  appearance  of  pus- 
corpuscles.  Again,  the  formation  of  pus  may  be  limited  to  one 
horn  of  the  crown,  or  may  affect  all  parts  of  the  pulp.  In  the 
former  instance,  the  trouble  is  known  as  abscess  of  the  pulp  ;  in 
the  latter  as  suppuration  of  the  puJp. 

An  instance  of  acutely-formed  abscess  is  illustrated  in  Fig. 
213.  Luckily,  th6  pus-corpuscles  have  remained  in  situ  in  this 
specimen,  perhaps  owing  to  its  being  imbedded  in  celloidin, 
A  well-defined  border  line  is  seen  between  the  inflamed  and  the 
suppurating  portions  of  the  pulp.  The  former  takes  the  stain  of 
ammoniacal  carmin,  the  latter  does  not.     In  the  vicinity  of  the 


402 


THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


abscess  most  of  the  blood-vessels  are  obliterated  by  being  trans- 
formed into  longitudinal  clusters  of  inflammatory  corpuscles. 
It  is  reasonable  to  assume  that  the  disintegration  of  the  inflamed 

Pig.  213. 


Acute  Suppurative  Pulpitis  ix  the  Coeon'al  Portion. 

/,  intensely-inflamed  horn ;  ^.abscess;  T',  blood-vessels  engorged  with  blood  ;  (S,  superficially- 
inflamed  horn ;  N,  nest  of  inflammation.    Magnified  10  diameters. 


tissue,   notwithstanding  the  presence  of  enormous  numbers  of 
staphylococci,  is  due  to  the  destruction  of  the  blood-vessels. 
Should  this  disintegration  take  place  throughout  the  entire 


MORBID    AXATO-MY    OF    PULPITIS.  403 

pulp,  suppuration  will  follow  everywhere,  and  in  sucli  a  case 
the  whole  pulp-chamber  will  be  transformed  into  an  abscess- 
cavity.  Such  a  termination  of  acute  purulent  pulpitis  seems  to 
be  exceedingly  rare.  Far  more  commonly,  the  coronal  portion, 
or  one  or  several  root  portions,  are  transformed  into  pus,  while 
one  or  more  root  portions  remain  in  the  stage  of  acute  pulpitis 
without  being  destroyed  by  suppuration. 

II.  Chronic  Pulpitis. — Modern  writers  claim  that  chronic  pul- 
pitis is  not  inevitably  the  outcome  of  primary  acute  pulpitis. 
This  holds  good  in  my  experience  for  a  certain  number  of  cases. 
Unquestionably,  however,  the  outcome  of  a  slight  acute  process 
must  be  the  form  which  I  propose  to  term  hyperplasia.  In  the 
light  of  late  researches  we  must  admit-that  any  particular  form 

Fig.  214. 


Left  Upper  Molar  'n'lTH  Partial  Hyperplasia  of  the  Pclp. 
Magnified  2  diameters. 

of  tissue,  before  its  transmutation  into  another  form,  will  have  to 
be  reduced  to  an  intermediate  state  of  indifference,  its  embry- 
onal or  medullary  condition.  Acute  pulpitis  furnishes  such  an 
intermediate  stage  of  indifference.  Since  the  term  inflammatory 
corpuscles  is  synonymous  with  that  of  embryonal  or  medullary 
corpuscles,  the  result  of  the  production  of  a  new  tissue  is 
termed  hyperplasia.  Such  hyperplasia  may  yield  a  tissue 
kindred  to  the  originally  inflamed  one,  the  result  being  a  new 
formation  of  myxomatous  tissue :  in  other  instances,  the  result 
Avill  be  the  transmutation  of  the  myxomatous  lymph-tissue  into 
fibrous  connective  tissue. 

In   many  instances,  an   exposed  and   consecpTently  inflamed 
pulp  at  the  bottom  of  a  large  carious  cavity,  instead  of  perish- 


404 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


ing  by  suppuration,  produces  so-called  ^^ proud  flesh"  known  to 
tlie  pathologist  as  fjranalations.  (See  Fig.  214.)  Such  granula- 
tions are  often  pediculated,  starting  from  the  narrow  root  por- 
tion and  freely  expanding  over  the  open  cavity.  They  are 
known  to  sprout  out  wherever  a  wound  on  the  surface  of  the 
body  heals  by  suppuration.     Similarly  the  exposed  pulp  pro- 

FiG.  215. 


Hyperplastic  Myxomatous  Pulp,  ^rt-HicH  Filled  a  Carious  Cavity. 


M,  lobules  made  up  of  papillee  of  a  myxomatous  structure,  rich  in  capillary  and  venous 
blood-vessels;  G^,  calcareous  globule  ;  ^,  epithelial  cover  of  papilla?.    Magnified  10  diameters. 

duces  crimson-red,  slightly  lobulated  granulations,  with  a  con- 
tinuous though  slight  discharge  of  pus. 

Under  the  microscope  the  granulation-tissue  is  seen  with  low 
powers  to  consist  of  myxomatous  connective  tissue  freely  sup- 
plied with  blood-vessels,  bjit  lacking  nerves.  (See  Fig.  215.) 
The  size  to  which  such  an  outgrowth  may  expand  is  almost 


MORBID    ANATOMY    OF    PULPITIS.  405 

unlimited,  a  circumstance  due  to  the  continuous  outgrowth  ot 
myxomatous  tissue  with  an  equally  continuous  new  formation 
of  capillary  blood-vessels  by  means  of  sprouts  of  the  capillary 
blood-vessels,  wdiich  are  at  first  solid,  and  afterward  vacnoled. 
and  hollowed  out.  The  layer  of  the  myxomatous  tissue  nearest 
to  the  surface  is  broken  down  into  protoplasm,  and  furnishes  the 
source  of  suppuration.     (L.  Heitzmann.) 

There  can  be  no  doubt  as  to  the  origin  of  the  peculiar  forma- 
tion illustrated  in  Fig.  215  from  previous  pulp-tissue,  since  a 
calcareous  globule  is  present  which  obviously  could  have  been 
formed  only  in  a  pulp. 

]Srot  infrequently  the  granuloma  filling  a  carious  cavity  does 
not  suppurate  on  its  surface.  In  such  a  case,  the  surface  is 
found  covered  with  an  incompletely  stratified  epithelium,  to  the 
presence  of  which  Arkovy  first  drew  attention.  K'ay,  it  may 
occur  that  a  portion  of  the  granuloma  yields  pus,  while  another 
portion  is  covered  with  epithelium,  as  is  seen  in  Fig.  215. 

Considerable  interest  attaches  to  the  covering  epithelium 
found  at  the  surface  of  a  tissue-formation,  sprung  from  pulp- 
tissue  which  lacks  epithelia  altogether.  (See  Fig.  216.)  There 
are  two  possibilities  for  the  explanation  of  this  peculiar  fact. 
Those  who  adhere  to  the  theory  of  the  mesoblastic  origin  of 
connective  tissue  will  deny  the  possibility  of  an  epiblastic  tissue, 
such  as  epithelium  is,  taking  its  origin  from  connective  tissue. 
For  these  investigators  there  exists  but  one  possibility, — viz,  a 
transplantation  of  epithelia  from  any  portion  of  the  oral  mucosa 
to  the  surface  of  the  granuloma.  Arkovy  himself  takes  this 
view.  Those  who  admit  the  possibility  of  an  interchange  of 
tissues  of  mesoblastic  and  epiblastic  origin,  as  A.  Kolliker  did 
in  previous  years,  will  also  concede  that  a  transformation  of 
connective  tissue  into  epithelia  may  occur.  I  myself  have 
strongly  advocated  the  idea  of  the  change  of  the  epithelium  of 
the  original  enamel-cord  into  myxomatous  connective  tissue  of 
the  enamel-organ.  On  the  other  hand,  I  cannot  object  to  the 
view  that  connective  tissue  may  be  changed  into  epithelia. 
When  we  closely  observe  the  row  of  columnar  epithelia  at  the 
surface  of  a  granuloma  of  the  pulp,  with  medium  powers  of  the 
microscope,  we  are  struck  with  the  elongated  feet  of  a  majority 
of  these  bodies,  blending  with  the  fibers  that  constitute  the 
reticulum  of  the  myxomatous  granulation-tissue.  (See  Fig. 
216.) 


406 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


The  final  answer  to  the  question  under  consideration  has, 
however,  not  as  yet  been  reached. 

Far  more  frequently  the  outcome  of  pulpitis  is  the  production 
of  dense  fibrous  connective  tissue.  (See  Fig.  217.)  This  tissue- 
change  may  involve  either  the  entire  pulp,  or  it  may  be  confined 

Fig.  216. 


Hyperplastic  Myxomatous  Pulp. 

J/,  myxomatous  granulation-tissue ;  G,  cluster  of  small  homogeneous  corpuscles ;  C,  capil- 
lary blood-vessel  in  transverse  section  ;  F,  vein  in  transverse  section  ;  E,  E,  rows  of  irregular 
columnar  epithelia,  overlapped  by  cuboidal  epithelia.    Magnified  500  diameters. 


to  a  part,  not  infrequently  even  to  a  small  superficial  portion.  A 
feature  of  fibrous  pulps  is  that  they  easily  lead  to  the  pro- 
duction of  bone-tissue  to  a  varjnng  extent.  Indeed,  I  have 
never  met  with  spicule  of  bone  in  pulps  which  were  not  fibrous. 


MORBID    ANATOMY    OF    PULPITIS. 


407 


If  the  fibrous  tissue-change  involves  only  a  peripheral  portion 
of  the  pulp,  the  new  formation  of  bone  will  take  place  along 
the  wall  of  the  pulp-chamber,  as  in  the  case  illustrated.  Excep- 
tionally, instead  of  bone,  a  tissue  allied  to  it — i.e.,  osteoid  tissue 
— will  make  its  appearance.     (See  Fig.  218.)     This  is  the  only 


Fig.  217. 


FiBEors  Root  Fortiox  of  PrLP  -n-iiH  Ossification  along  the  Dentinal  Wall. 

D.  primary  dentine  ;  N,  neck -like  formation  of  bone-lissue  ;  B.  B,  faintly  lamellated  bone- 
tissue;  F,  fibrous  pulp  with  scanty  blood-vessels,  bundles  interlacing;  E,  bay-like  excava- 
tions in  the  bone-tissue.    Magnified  200  diameters. 

instance  where  I  have   seen  such  osteoid  tissue,  which   as  to 
structure  is  evidently  between  calcification  and  ossification. 

Should  pulpitis  again  attack  a  fibrous  pulp,  the  latter  will  be 
reduced  to  medullarv  tissue,  and  we  shall  see  bay-like  excava- 


408 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


tions  corroding  the  periphery  of  calcified  masses,  or  of  newly- 
formed  spiculre  of  bone-tissue,  the  excavations  being  filled  with 
multinuclear  protoplasmic  bodies.  In  the  transmutation  of 
myxomatous    lymph-tissue   into  fibrous  connectiye  tissue  the 


Fro.  21H. 


Osteoid  Formatioxs  in  the  Pulp.    (From  Fig.  210.) 

Z,  ledges  of  calcareous  deposits  along  the  border  of  the  pulp  ;  G.  globular  calcareous  terri- 
tories with  central  protoplasmic  bodies:  jlf,  fibrous  connective  tissue  crowded  with  medul- 
lary corpuscles  ;  F,  fibrous  connective  tissue  the  result  of  chronic  plastic  pulpitis.  Magnified 
500  diameters. 


nerves  seem  to  participate  actively  in  the  tissue-changes,  which 
would  explain  the  fact  that  fibrous  pulps,  or  fibrous  portions  ot 
the  pulp,  lack  nerves  altogether. 

Chronic   Purulent  Pulpitis. — This,  again,  may  appear  in  two 


MORBID    AXATOMY    OF    PULPITIS. 


409 


forms, — partial  and  total  suppuration.  A  chronic  abscess  is 
not  infrequently  found  in  the  coronal  portion  of  the  pulp.  It 
is,    of  course,   invariably  the    outcome  of    an    acute    abscess. 


Fig.  219. 


Cheoxic  SrppuRATivE  Pulpitis  termixatixg  ix  Calcificatiox  of  the  Prs  and  Atrophy 

OP  THE  Pulp. 

J.1,  larger  abscess,  filled  with  calcified  pus:  A-,  aljseess  at  the  penphery  of  the  pulp  ;  A\  A^, 
small  longitudinal  abscesses,  all  calcified  ;  N,  calcified  nerve-bundle  ;  C,  C,  calcareous  deposi- 
tions in  the  fibrous  pulp-tissue  :  P,  P,  pigment  clusters  from  previous  hemorrhage.  Magnified 
10  diameters. 


While  in  the  latter  form  there  is  no  distinct  boundary-line  at 
the  border  of  the  diseased  territory,  when  the  abscess  has  per- 


410 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


sisted  for  some  length  of  time  it  becomes  encapsulated  by  a 
layer  of  newly-formed  fibrous  connective  tissue,  the  so-called 
"  memhrana  pyogena'^  of  older  writers.  Then  the  boundary-line 
is  conspicuous,  especially  when  the  pus  crumbles  away  in  the 
process  of  section-cutting.  As  soon  as  the  abscess  has  become 
chronic,  the  pus-corpuscles  undergo  fatty  degeneration,  the  same 
as  the  contents  of  all  chronic  abscesses  in  the  body.  Still  later 
the  fatty  pus  becomes  the  seat  of  a  deposition  of  lime-salts,  and 
thus  it  is  rendered  harmless,  since  all  micro-organisms  are  de- 
stroyed by  this  process.     (See  Fig.  220.) 

Fig.  220. 


Segment  of  Abscess  of  Pulp,  holding  Calcified  Pus.    (From  Fig.  219,) 

W,  wall  of  abscess  crowded  with  micro-organisaip  ;  P,  calcified  pus- corpuscles  ;  C,  calcareous 
masses  ;  M,  bundle  of  micro-organisms.    Magnified  500  diameters. 


Chronic  total  purulent  pulpitis  is,  according  to  recent  re- 
searches (Arkovy  and  Rothmann),  a  process  not  necessarily  de- 
pending upon  a  preliminary  stage  of  acute  suppuration  ;  just  as  in 
the  case  of  acute  total  purulent  pulpitis  the  chronic  form  com- 
monly afiects  only  parts  of  the  coronal  and  root  portions  of  the 
pulp,  other  portions  almost  always  escaping  destruction  and 
remaining  alive.  (See  Fig.  219.)  In  this  figure  we  observe  a 
large  number  of  purulent  foci  of  greatly  varying  size  scattered 
throughout  the  entire  substance  of  the   pulp-tissue.     The  re- 


MORBID    AXATOMY    OF    PULPITIS.  411 

maincler  of  the  living  pulp-tissue  has  become  fibrous,  erecting 
walls  around  each  abscess.  As  these  are  crowded  with  micro- 
organisms, it  is  probable  that,  with  each  newly-appHed  irrita- 
tion, the  micro-organisms  induce  suppuration  again,  and  so  a 
successive  production  of  abscesses  may  go  on  almost  indefi- 
nitely. The  fibrous  portions  of  the  pulp  may  cause  either  a 
new  growth  of  bone-tissue  or  the  appearance  of  calcareous 
globules,  as  in  the  case  illustrated.  A  fresh  attack  of  purulent 
inflammation  always  leads  to  a  partial  dissolution  of  the  lime- 
salts  and  the  appearance  of  the  bay-like  excavations  at  the 
borders  of  both  calcified  and  ossified  tissues.  Since,  as  stated 
before,  change  of  the  pulp  to  a  fibrous  tissue  leads  to  a  destruc- 
tion of  the  nerve-bundles,  it  is  reasonable  to  assume  that  chronic 
suppuration  of  the  pulp  is  not  accompanied  with  as  much  pain 
as  is  the  acute. 

If  we  examine  the  contents  of  a  chronic  abscess  of  the  pulp, 
we  invariably  find  the  pus-corpuscles  in  a  state  of  fatty  degen- 
eration,— i.e.,  crowded  with  fat-granules.  Occasionally  the  con- 
tents of  a  chronic  abscess  are  pus-corpuscles  in  a  high  degree  of 
calcification,  owing  to  the  deposition  of  lime-salts.  (See  Fig.  220.) 
This  process  renders  each  pus-corpuscle  a  glossy,  indistinctly- 
granular  and  irregularly-contoured  body,  glued  to  its  neighbors 
and  intermixed  with  larger  caked  calcareous  masses  and  groups 
of  inert  micro-organisms.  The  calcareous  metamorphosis  of 
pus  explains  why,  in  sections  of  pulps  afi^ected  with  chronic 
purulent  pulpitis,  the  contents  of  the  abscesses  remain  in  situ. 

III.  Gangrene  of  the  Pulp. — This  process  is  invariably  the 
outcome  of  acute  pulpitis,  when  certain  micro-organisms,  as 
the  Streptococcus  septicus,  obtain  access  to  the  inflamed  pulp. 
In  most  cases  of  gangrene  the  pulp  is  transformed,  in  a  short 
space  of  time,  into  a  dark  grayish-brown,  pulpy,  and  foetid  mass, 
almost  ditfluent,  not  oifering  any  reason  for  its  preservation. 
The  foetid  odor  is  due  to  the  production  of  the  gases  of  putrefac- 
tion. It  has  been  asserted  that  the  accumulation  of  such  gases 
in  the  pulp-chamber  has,  by  their  expansion,  led  to  a  bursting 
of  the  crown  of  the  tooth,  the  explosion  being  accompanied 
by  a  report  resembling  that  of  a  pistol-shot.  jSTo  certain  data 
about  such  an  accident  have  ever  been  recorded. 

By  an  almost  total  stopping  up  of  the  caliber  of  the  afi'er- 
ent  artery,  as,  for  instance,  by  an  embolus,  death  of  the  pulp- 
tissue  may  ensue  in  the  shape  of  so-called  dry  gangrene.     In  this 


412  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

process,  the  pulp,  so  far  as  my  own  experience  teaches,  is  trans- 
formed into  a  grayish-white,  dry  mass,  devoid  of  odor,  mummi- 
fication of  the  pulp-tissue,  with  an  imperfect  preservation  of  its 
constituent  elements.  To  this  process  I  shall  devote  a  separate 
chapter,  dwelling  upon  artificial  mummification  or  coagulation- 
necrosis  of  the  pnlp-tissue. 


CHAPTER    XXXVI. 

DEGENERATIONS  AND  ATROPHIES  OF  THE  PULP. 

I  PLACE  the  above  diseases  of  the  pulp  in  a  separate  chapter, 
because  these  retrogressive  tissue-changes  are  by  no  means 
alwaj^s  the  outcome  of  pulpitis.  Having  examined  a  large 
number  of  pulps  containing  so-called  pulp-stones,  I  can  say  that 
these  are,  as  a  rule,  the  result  of  irritation,  but  not  of  inflamma- 
tion.    True  it  is  that  they  are  frequently  the  cause  of  pulpitis. 

a.  Calcification. — Calcification  occurs  in  two  forms,  i.e. ,  within 
the  basis-substance  of  the  myxomatous  connective  tissue,  and  in 
the  nerves  and  blood-vessels. 

Calcification  of  the  basis-substance  of  the  myxomatous  con- 
nective tissue  is  of  quite  frequent  occurrence,  and  seems  to  be 
more  common  in  the  pulps  of  teeth  which  have  stood  in  crowded 
dental  arches,  the  wisdom-teeth  being  especially  prone  to  it. 
The  age  of  the  patient  apparently  does  not  infiuence  calcifica- 
tions of  the  pulp,  as  the  writer  has  found  them  in  the  pulps  of 
teeth  of  quite  young,  as  well  as  old  people.  From  external 
appearances,  or  subjective  phenomena,  we  are  unable  to  diagnose 
this  form  of  calcification  of  the  pulp,  as  it  never  causes  trouble. 
The  aspects  are  quite  difierent,  however,  when  calcifications 
occur  in  the  blood-vessels  or  nerves  of  the  pulp. 

Diagnosis.^ — The  latter  form  of  calcification  occurs  only  in 
teeth  affected  with  chronic  marginal  pericementitis  which  has 
existed  more  than  one  year.  The  gums  in  the  vicinity  of  the 
inflamed  pericementum  during  a  paroxysm  of  pain  in  the  pulp 
appear  acutely  inflamed,  and  are  somewhat  sensitive  to  pressure. 
The  tooth  is  raised  from  its  socket,  slightly  loose,  and  sensitive 
to  percussion  and  pressure.  The  characteristic  features  of  this 
painful  disease  are,  that  the  tooth  is  of  a  normal  color,  and  ex- 


DEGENERATIOXS  AND  ATROPHIES  OF  THE  PULP,       413 

tremely  sensitive  to  thermal  changes,  especially  cold.  The  sub- 
jective phenomena  of  calcifications  of  the  blood-vessels  and  nerves 
of  the  pulp  are  characterized  in  the  beginning  of  the  process  by 
slight  intermittent  pain.  The  process  commences  \vith  acute 
marginal  pericementitis,  a  so-called  blind  abscess,  which  after  be- 
coming chronic  gradually  aftects  the  pulp  of  the  tootli.  The 
pain  in  the  pulp  usually  begins  two  or  three  months  after  the 
first  appearance  of  the  pericementitis,  in  paroxysms,  lapting  at 
first  a  few  hours,  but  in  later  stages  they  may  continue  for  four 
days  or  even  more.  Such  paroxysms  of  pain  are  usually  induced 
by  a  depressed  state  of  the  general  health.  When  the  pain  is 
over,  the  tooth  continues  to  feel  sore  for  two  or  three  days, 
though  usually  the  pain  does  not  re^ur  for  a  month  or  two. 
With  every  renewal  of  the  attack,  however,  the  pain  becomes 
more  severe  and  the  paroxysms  last  longer.  When  such  a  tooth 
contains  a  cavity,  or  a  gutta-percha  filling,  which  is  situated  near 
the  pulp-chamber,  we  may  be  able  to  relieve  the  patient  from 
the  terrible  sufiering  which  the  disease  produces  in  pronounced 
stages. 

Differential  Diagnosis. — Calcifications  of  the  blood-vessels  and 
nerves  of  the  pulp  may  be  confounded  with  an  acute  apical 
alveolar  abscess,  although  in  the  latter  instance  the  tooth  is 
usually  discolored  and  not  sensitive  to  thermal  changes.  In  this 
respect,  a  characteristic  feature  of  teeth  affected  with  calcifica- 
tions of  the  blood-vessels  and  nerves  of  the  pulp  is  the  super- 
sensitiveness  of  the  dentine  to  the  bur. 

Prognosis. — Teeth  whose  pulps  are  affected  by  a  calcification 
of  the  blood-vessels  and  nerves  are  usually  lost,  unless  the  pulp 
can  be  extirpated,  which  is  barely  possible  in  the  advanced 
stages  of  this  process,  on  account  of  the  great  sensitiveness  of 
both  the  pulp  and  the  dentine. 

b.  Eburnification  and  Ossification  of  the  Pulp. — On  account 
of  the  obscurity  of  their  diagnosis,  these  disturbances  of  the 
pulp  cause  great  trouble.  The  writer  has  met  with  patients  who 
for  months  or  even  years  have  suffered  intensely  from  what  was 
supposed  to  be  neuralgia  of  the  face,  arms,  and  the  chest,  the 
trouble  subsequently  localizing  itself  in  the  pulp  of  a  tooth,  and 
the  pains  ceasing  instantly  and  never  returning  after  the  extir- 
pation of  the  affected  pulp.  In  order  to  emphasize  the  impor- 
tance of  this  subject,  I  will  briefly  relate  three  characteristic 
cases  met  with  in  my  practice. 


414  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH, 

I.  For  Miss  S.,  aged  fourteen  years,  I  filled,  on  Xovember 
25,  1872,  the  second  lower  molar  with  amaloram.  The  cavity 
was  situated  on  the  buccal,  near  the  mesial  surface,  and  was 
rather  extensive.  The  tooth,  alter  the  filling  had  been  inserted, 
remained  sensitive  to  thermal  changes  for  a  long  time,  but 
otherwise  gave  no  trouble.  In  December,  1879,  the  tooth 
became  decayed  on  its  mesial  surface,  but  in  trying  to  prepare 
this  cayity  I  found  the  dentine  so  extremely  sensitive  that  the 
patient,  being  at  the  time  in  bad  health,  would  not  submit  to 
it.  June  3,  1880,  I  saw  the  tooth  again,  when  the  decay  had 
reached  the  pulp-cavity.  It  had  never  given  very  much  trouble, 
except  when  food,  during  mastication,  w^as  pressed  into  the 
cavity.  I  found  the  dentine  sensitive  as  before,  and  concluded, 
therefore,  to  devitalize  the  coronal  portion  of  the  pulp,  and 
made  an  application  of  arsenious  acid.  The  next  day,  when 
the  patient  entered  my  ofiice,  she  told  me  she  felt  better  than 
for  many  months.  When  I  removed  the  dressings  and  exam- 
ined the  state  of  the  pulp,  I  found  a  large  so-called  "  pulp-stone" 
lying  toward  the  amalgam  filling.  The  patient,  since  that  time, 
has  had  no  more  neuralgia,  has  grown  quite  strong  and  vigorous, 
and  the  molar,  with  the  coronal  portion  of  the  pulp  amputated, 
does  good  service,  and  has  not  given  any  further  trouble. 

ir.  On  September  3,  1881,  Mrs.  E.,  aged  twenty-two,  came 
to  me  with  excruciating  pain  in  the  left  upper  lateral,  contain- 
ing a  large  gold  filling  in  its  mesial  surface  which  had  been 
inserted  several  years  previous!}'.  About  a  year  before  the 
patient  first  noticed  lameness  of  the  left  arm,  which,  after  some 
weeks,  had  terminated  in  more  or  less  constant  neuralgia, 
aflecting,  at  times,  the  entire  left  side  of  the  body ;  but  no  pain 
was  observed  in  this  tooth  previous  to  the  1st  of  September, 
two  days  before  the  patient  applied  to  me  for  relief.  I  opened 
the  pulp-chamber  fi-om  the  lingual  surface  of  the  tooth,  and 
found  the  pulp  in  a  state  of  acute  total  pulpitis,  which  had 
extended  somewhat  into  the  pericementum.  An  application  of 
carbolic  acid,  tannin,  and  morphia  was  made,  which  greatly 
relieved  the  patient.  About  one  hour  later  I  renewed  the 
application,  and  after  a  few  minutes  introduced  arsenious  acid, 
and  then  dismissed  the  patient,  who  felt  greatl}'  relieved.  The 
next  day  I  extracted  the  pulp  by  means  of  a  broach,  and  im- 
mediately immersed  it  in  a  very  weak  solution  of  chromic  acid. 
A  section  of  this  is  exhibited  in  Fig.  174.     The  patient,  who  at 


DEGENERATIONS  AND  ATROPHIES  OF  THE  PULP.       415 

tliat  time  lived  in  the  country,  carae  back  two  days  afterward 
to  thank  me  for  the  cure  of  her  neuralgia,  which,  up  to  this 
time,  has  not  recurred. 

III.  On  June  1,  1878,  I  inserted  for  Dr.  H.  an  oxychloride 
fining  in  the  right  upper  first  molar,  which  had  previously  been 
filled  with  amalgam.  The  cavity  was  large,  involvinsr  the  distal 
and  grinding-surfaces,  with  half  of  the  lingual  wall  broken  off". 
On  August  21,  1880,  I  restored  the  lost  portion  of  the  tooth 
with  gold,  but  left  much  of  the  oxychloride  cement  over  the 
pulp-cavity.  The  walls  of  the  cavity  were  quite  sensitive  under 
the  bur,  so  much  so  that  my  patient,  who  in  all  other  opera- 
tions I  had  previously  performed  for  him  never  said  a  word  of 
the  pain  produced  by  excavating,  in  this  instance  remarked 
that  the  drilling  in  some  places  was  very  painful.  There  had 
been  no  pain  whatever  previous  to  the  introduction  of  the 
gold,  but  about  a  week  after  the  operation  was  completed 
the  tooth  became  sensitive  upon  percussion  and  mastica- 
tion, without  signs  of  pulpitis.  About  two  weeks  later  my 
patient  was  suftering  from  an  acute  alveolar  abscess  situated 
above  the  buccal  roots  of  this  molar  tooth.  T  immediately 
tried  to  open  the  pnlp-chamber,  but  conld  only  go  a  little  way 
into  the  dentine,  when  the  patient  informed  me  that  the  drill- 
ing caused  him  severe  pain,  analogous  to  the  excavating  of  a 
sensitive  tooth.  I  abstained  from  drilling  any  further,  filled 
the  small  hole  with  gutta-percha,  and  began  the  treatment  of 
the  abscess  through  the  gum  at  the  buccal  surface,  but  with  no 
success.  The  abscess  was  continually  discharging  until  the 
beginning  of  December,  when  I  removed  the  gutta-percha,  and, 
with  a  sharp  drill,  perforated  the  pulp-chamber,  but,  to  my  sur- 
prise, found  the  pulp  alive  and  bleeding  freely.  I  then,  as  quickly 
as  possible,  capped  the  pulp  in  the  usual  way,  and  filled  the  outer 
portion  of  the  drill-hole,  which  had  been  widened  with  a  larger 
bur  up  to  the  cap,  with  oxyphosphate  cement,  concluding  to 
wait  a  few  weeks  longer,  and  then,  if  the  abscess  did  not  heal,  to 
devitalize  the  pulp.  On  January  23,  1881, 1  removed  the  fill- 
ing, together  with  the  cap,  in  order  to  destroy  the  pulp,  but 
found  that  the  pulp  had  died  recently,  as  there  was  no  smell  of 
putrefaction  present  in  the  pulp-chamber.  I  took  out  a  large 
filling  in  the  mesial  surface  of  the  tooth,  and  from  this  situation 
thoroughly  exposed  the  pulp-chamber,  from  which  I  extracted 
a  very  large  so-called  "  pulp-stone"  of  the  size  of  a  small  pea, 


416  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

occupying  the  neigliborliood  of  the  buccal  roots.  This  is  the 
specimen  which  I  have  illustrated  iu  Fig.  175,  "  so-called 
'  pulp-stones'  composed  of  dentine  with  the  features  of  primary 
dentine."  The  canals  of  the  tooth  were  then  examined,  and  I 
found  the  two  buccal  canals  in  a  very  putrid  condition,  but  the 
lingual  canal  contained  its  recently-dead  portion  of  the  pulp 
without  large  calcified  or  eburnified  masses.  After  the  disin- 
fection and  filling  of  the  pulp-canals  the  abscess  began  to  heal, 
and  the  tooth  to-day  is  as  serviceable  and  comfortable  as  any 
other  tooth  in  the  mouth. 

Diagnosis. — As  stated  before,  to  differentiate  clearly  between 
cases  of  true  neuralgia  and  those  depending  upon  eburuifications 
and  ossifications  of  the  pulp  is  sometimes  impossible,  although  in 
most  instances  we  are  successful  in  localizing  the  origin  of  the 
trouble.  The  crowns  of  the  teeth  producing  such  reflex  pains 
are  sometimes  perfectly  sound,  or  they  have  previously  been 
filled.  In  the  latter  case  it  is  likely  that  a  large  metallic  or  oxy- 
phosphate  filling  has  been  placed  too  near  the  pulp.  In  these 
cases  the  diagnosis  is  usually  made  by  the  application  of  hot  and 
cold  water,  taking  the  precaution  to  separate  the  suspected  tooth 
either  with  the  rubber-dam,  napkins,  or  bibulous  paper.  Ther- 
mal changes  always  produce  great  pain,  and  the  sudden  appli- 
cation to  the  seat  of  the  trouble  of  agents  which  produce  them 
often  enables  us  to  locate  the  ofifender.  Quite  different,  how- 
ever, are  those  cases  in  which  the  crowns  of  the  afifected  teeth 
have  never  been  filled,  and  are  apparently  healthy.  While  in 
the  former  instance  the  disease  is  usually  limited  to  the  tooth 
that  had  previously  been  filled,  in  the  latter  instance  the 
trouble  often  originates  more  or  less  from  two  or  more  teeth  on 
the  same  side,  in  which  event  all  the  teeth  of  the  affected  side 
will  react  upon  the  application  of  hot  or  cold  water,  although 
sometimes  this  reaction  may  be  wanting.  In  such  cases  per- 
cussion has  proved  of  great  service  to  the  writer.  In  the  per- 
cussion test,  however,  we  must  carefully  exclude  all  devitalized 
teeth,  which  are  sometimes  sensitive  to  percussion  while  the 
patient  is  affected  with  neuralgic  pains,  although  their  peri- 
cementum may  be  healthy.  Teeth  the  pulps  of  which  are 
affected  by  eburnifications  or  ossifications  are  a  trifle  loose  in 
their  sockets,  and  yield,  upon  percussion,  a  sliglitly  dull  sound. 

The  subjecike  •phenomena  connected  with  eburnifications  or 
ossifications  of  the  pulp-tissue  are  marked  by  great  pains  of  the 


DEGENERATIOXS  AND  ATROPHIES  OF  THE  PULP.       417 

atfected  side,  \Yliieh  are  seldom  localized  iu  the  pulp  of  the  tooth 
producing  the  disturbance,  but  are  usually  more  pronounced  in 
neighboring  parts  of  the  nervous  system.  The  affected  nerves, 
in  the  beginning  of  the  proces-,  are  slightly  sensitive  to  sudden 
thermal  changes,  which  sensitiveness  lasts,  as  a  rule,  not  over 
one  minute.  But  with  every  attack  the  pain  increases  in 
severity,  and  although  seldom  lasting  longer  than  from  one  to 
three  minutes  at  a  time,  is  most  excruciating.  One  patient 
described  these  pains  to  be  similar  to  that  of  a  strong  interrupted 
current  of  electricity  going  through  the  teeth  and  face.  The 
paroxysms  of  pain  may  occur  once  or  twice  in  twenty-four 
hours,  or  they  may  return  every  five  minutes.  When  the  patient 
has  suffered  for  some  time,  we  ofcen  observe  a  lameness  of  the 
muscles  of  the  affected  region,  which  in  some  instances  even 
become  sore  to  the  touch.  Such  an  attack  may  last  a  week  or 
a  month,  and  the  duration  and  recurrence  of  the  pain  seem  to 
be  influenced  by  changes  in  the  weather  as  well  as  by  locality. 
Damp  and  cold  weather  is  apt  to  bring  on  an  attack  of  pain, 
while  dry  and  warm  weather  is  said  to  postpone  it. 

Differential  Diagnosis. — From  what  has  been  stated  above  it  is 
evident  that  most  of  the  teeth,  the  pulps  of  which  are  affected 
by  eburnifications  or  ossifications,  contain  no  deep-seated  carious 
cavities.  Teeth,  therefore,  exhibiting  large  or  deep-seated 
carious  cavities,  reaching  the  vicinity  of  the  pulp,  are  to  be 
excluded  from  this  category  of  pulp-diseases.  There  is,  how- 
ever, one  form  of  pulpitis,  total  hyperplasia,  the  subjective  symp- 
toms of  which  are  somewhat  similar  to  those  of  eburnifications 
and  ossifications  of  the  pulp.  The  similarity  in  the  pain  of 
these  two  diseases  is  explained  by  the  fact  that  upon  examination 
with  the  microscope  we  always  find  the  pulps  to  be  composed 
more  or  less  of  fibrous  connective  tissue,  which  easily  gives 
origin  to  new  formations  .of  bone  or  dentine;  the  difference, 
however,  being  that  a  pulp  suffering  from  total  hyperplasia  is 
more  or  less  exposed,  and  the  patient  usually  is  able  to  localize 
the  pain. 

Hyperostosis  of  the  Roots  of  the  Teeth  has  sometimes 
been  confounded  with  eburnifieatibn  or  ossification  of  the  pulps, 
both  indeed  often  presenting  the  same  symptoms.  In  one  in- 
stance observed  by  the  author,  a  patient  about  thirty  years  of 
age,  whose  dental  arches  were  much  crowded,  had  suffered  inter- 
mittently from  severe  neuralgia,  sometimes  on  one,  sometimes 

28 


418  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

on  both  sides  of  the  face.  The  teeth  were  not  affected  hj 
thermal  changes  nor  by  alterations  in  the  weather,  and  upon  the 
extraction  of  the  four  wisdom-teeth  the  pain  ceased  and  never 
returned.  Unerupted  lower  wisdom-teeth,  when  the  arch  is  too 
small  to  accommodate  all  the  teeth,  may  give  rise  also  to  pain, 
which  maybe  confounded  with  ossifications  or  eburnificalions  of 
the  pulp.  These,  however,  are  easily  recognized  by  the  inflam- 
mation they  usually  produce  in  their  surroundings.  When  the 
seat  of  the  trouble  is  thought  to  be  in  a  tooth,  the  only  method 
to  give  relief  and  make  the  diagnosis  certain  is  to  open  the  tooth 
and  devitalize  the  pulp. 

Prognosis. — When  the  seat  of  the  trouble  is  discovered,  the 
pulps  extirpated  and  the  root-canals  filled,  the  severe  pains  will 
never  return.  In  many  instances,  however,  patients  during 
their  paroxysms  of  pain  have  had  the  teeth  extracted  without 
discovering  the  one  containing  the  eburnifications  or  ossifications, 
which  was  left  in  the  mouth,  the  pains  of  course  continuing. 
The  writer  once  met  a  gentleman  who,  upon  the  advice  of  his 
physician,  had  all  his  posterior  teeth  removed,  first  those  of  the 
upper,  then  those  of  the  lower  jaw,  but  the  pain  persisted  for 
about  eighteen  months  longer,  when  it  localized  itself  in  an 
upper  cuspid.  This  tooth  was  opened,  the  pulp  devitalized  and 
extirpated,  and  the  canal  was  filled,  since  which  time  the  pains 
have  never  returned.  Upon  examination,  I  found  the  pulp  to 
be  crowded  with  small  eburnifications. 

c.  Atrophies  of  the  Pulp  are  of  rare  occurrence,  and  little  is 
known  of  them  so  far  as  clinical  observations  are  concerned,  as 
in  most  instances  we  are  unable  to  make  a  correct  diagnosis  . 
from  the  external  appearances  of  the  afi'ected  teeth.  J.  Arkov}- 
mentions  four  forms  of  atrophy  of  the  pulp, — viz,  simple,  scle- 
rotic, reticular,  and  total  atrophy.  As,  however,  simple  and 
total  atrophies  of  the  pulp,  from  a  clinical  as  well  as  from  a 
histological  point  of  view,  are  of  little  importance,  I  shall  con- 
fine myself  to  the  description  of  the  two  most  important  dis- 
eases of  this  type, — viz,  sclerotic  airophy  and  reticular  atrophy. 

Sclerotic  Atrophy  of  tpie  Pulp. — Diagnosis. — This  disease 
is  met  with  in  apparently  sound  teeth,  as  well  as  in  those  whose 
crowns  have  been  the  seat  of  caries.  The  filling  of  the  cavity 
of  a  tooth  apparently  has  no  infiuence  over  this  disease  of  the 
pulp.  From  the  external  appearance  of  a  tooth  the  pulp  of 
which  is  afi'ected  with  sclerotic  atrophy,  we  are  unable  to  make 


DEGENERATIONS    AND    ATROPHIES    OF    THE    PULP.  419 

a  correct  diagnosis.  When  this  disease  occurs  in  teeth  with 
deep-seated  caries  that  does  not  quite  reach  the  pulp-chamber, 
there  is  usually  an  uneasy  sensation  in  the  tooth,  similar  to  that 
in  irritation  of  the  pulp.  A  differential  sign  is  that  when  the 
cavity  of  a  tooth,  the  pulp  of  which  is  aftected  with  sclerotic 
atrophy,  is  disinfected  and  tilled,  the  sensitiveness  remains, 
while  in  one  with  an  irritated  pulp  it  will  usually  cease  after 
one  or  two  days. 

The  prognosis  of  pulps  with  sclerotic  atrophy  seems  to  be  fair, 
as  a  pulp  so  affected  may  live  for  many  years  without  causing 
severe  disturbance.  The  author  has  observed  one  case,  a  right 
lower  first  molar,  in  the  mouth  of  a  healthy  lady.  In  May, 
1880,  the  tooth  was  somewhat  sensitive  at  times,  and  upon  ex- 
amination I  found  a  carious  cavity  in  its  mesial  surface,  which 
was  prepared,  disinfected,  and  filled  with  gutta-percha,  without 
any  subsequent  change  in  the  sensation  of  the  tooth.  In  Sep- 
tember, 1893,  the  lady  had  a  fall  which  loosened  the  cuspid,  the 
two  bicuspids,  and  the  molar  teeth,  and  as  they  pained  consider- 
ably, she  insisted  upon  having  them  removed.  Upon  opening 
the  molar,  I  found  that  a  portion  of  the  pulp  was  affected  by 
sclerotic  atrophy. 

Reticular  Atrophy  of  the  Pulp. — Diagnosis. — This  peculiar 
disease  of  the  pulp  occurs  most  commonly  in  teeth  which  have 
not  been  attacked  by  caries,  although  they  may  have  been  pre- 
viously filled,  the  filling  reaching  the  vicinity  of  the  pulp-cham- 
ber. Teeth  usually  attacked  by  reticular  atrophy  stand  alone 
in  the  dental  arch,  or  articulate  with  their  antagonists  in  such  a 
manner  that  they  are  inclined  either  to  the  lingual  or  to  the  buc- 
cal side  of  the  mouth.  In  such  a  case  the  pericementum  is  irri- 
tated every  time  the  antagonizing  tooth  comes  in  contact  with 
it.  We  also  meet  with  this  process  in  patients  who  have  worn 
their  incisors,  by  mechanical  abrasion,  nearly  down  to  the  pulp- 
chambers,  and  also  in  the  teeth  of  aged  persons.  In  color,  very 
little  or  no  difference  is  detectable  between  the  teeth  affected  and 
those  containing  normal  pulps.  We  also  find  some  teeth  in 
the  later  stages  of  pyorrhcea  that  contain  pulps  afifected  with 
reticular  atrophy.  The  apices  of  their  roots  are  usually  slightly 
absorbed,  but  this  is  frequently  observed  in  other  teeth,  the 
pulps  of  which  are  afi:ected  by  reticular  atrophy.  Thermal 
changes  exert  no  influence  on  such  teeth.  Most  of  them  sufter 
more  or  less  from  chronic  apical  pericementitis.    Percussion  will 


420  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

yield  a  dull  sound,  although  we  meet  with  many  cases  in  which 
no  pericementitis  is  demonstrable  from  external  appearances. 
."When  the  pulp-canal  of  a  tooth  the  pulp  of  which  is  afiected 
with  reticular  atrophy  is  opened,  the  pulp  appears  like  a  quite 
thin  flattened  thread  of  catgut. 

Subjective  Phenomena. — Teeth  whose  pulps  have  been  the  seat 
of  reticular  atrophy  do  not  cause  any  pain  as  such,  except  that 
sometimes,  as  is  the  case  in  pyorrhoea  alveolaris,  apical  perice- 
mentitis may  assume  an  acute  form. 

Differential  Diagnosis. — This  disease  maybe  easily  confounded 
with  dry  gangrene  of  the  pulp,  the  only  difference  being  that  the 
apices  of  the  roots  of  the  teeth,  the  pulps  of  which  have  died  of 
dry  gangrene,  are  seldom  aifected  by  chronic  pericementitis. 

The  ijrognosis  of  teeth  the  pulps  of  which  have  died  from 
reticular  atrophy  is  always  good,  as  the  filling  of  the  root-canals 
is  rarely  followed  by  acute  pericementitis. 


CHAPTER  XXXA^II. 

MORBID  ANATOMY  OP  ATROPHIES  AND  DEGENERATIONS  OF  THE  PULP. 

a.  Calcifications. — According  to  C.  AYedl,  small  nodular  cal- 
careous concretions  of  the  pulp  may  be  produced  either  by  a 
calcification  of  cells,  or  by  a  direct  impregnation  of  the  organic 
substance  with  calcareous  salts.  The  frequent  occurrence  of 
such  nodules  in  the  pulp  is  by  no  means  confined  to  old  age 
and  the  period  of  absorption  of  temporary  teeth,  but  is  not 
rarely  met  with  in  teeth  of  young  men  and  women.  Altogether 
calcareous  depositions  in  the  pulp,  in  the  shape  of  both  nodules 
and  irregular  needles  or  spiculae,  are  frequently  found  (Witzel, 
Baume),  but  the  cause  of  their  formation  is  as  yet  unknown. 
A  pronounced  case  is  illustrated  in  Fig.  221.  The  slightly- 
lobulated  calcareous  globules  are  concentrically  striated  around 
one  or  several  centers,  which  latter,  judging  from  a  slight  stain 
with  ammoniacal  carmin,  are  not  so  intenseh-  calcified  as  are 
their  peripheral  portions.  '^ 

The  age  of  the  person  apparently  has  nothing  to  do  with 
the  calcification  of  the  pulp.     Some  very  good  observers  have 


MOKBID  ANATOMY  OF  ATROPHIES  AND  DEGEXERATIOXS.   421 

described  it  as  the  result  principally  of  caries  or  loss  of  sub- 
stance of  the  tooth  by  mechanical  means.  I  have  a  great  many 
specimens  of  pulps  prepared  from  bicuspids  and  lirst  and  third 

Fig.  221. 


Pulp  -with  Coxcextricali.y-Striated   Calcareous  Globules,  so-called  Pulp-Stoxes. 
C.  C,  calcareous  globules  ;  L,  lymph-vessel ;  N,  iV,  bundles  of  medullated  nerves.   Magnified 
lu  diameters. 


molars  of  young  persons,  which  had  to  be  extracted  on  account 
of  irregularity  or  want  of  room,  and  most  of  them  are  exter- 
nally perfectly  sound.     Some  of  the  wisdom-teeth  were  removed 


422 


THE    AXATOMT    AXD    PATHOLOGY  .OF    THE    TEETH. 


when  only  one  or  two  of  their  cusps  had  pierced  the  gum,  hut 
with  only  one  exception  all  of  these  pulps  exhibit  greater  or 
less  quantities  of  calciiic  deposits  as  well  as  ehurnifications. 
The  same  conditions  I  have  observed  in  pulps  derived  from  the 
teeth  of  old  persons. 

I  extracted  an  unerupted  wisdom-tooth  from  beneath  the 
gums  of  a  youth  fifteen  years  of  age,  the  pulp  of  which  I 
found  crowded  with  such  calcareous  globules.  A  rare  in- 
stance of  calcification  of  blood-vessels  is  drawn  in  Fig.  224. 
Here  we  notice  a  large  piortion  of  the  blood-vessels  of  the 

Fig.  222. 


CaLCIFICATIOX.— PCLP   OF   A  FiRST  LOWEK  MoLAR  OF  A  Healthy  YoUNG   Max   Ei&hteex 

Years  of  Age,  Extracted  ox  accouxt  of  iRREorLAEiTY. 

C,  calcified  masses  composed  of  irregular  lumps,  probably  former  medullary  corpuscles  ;   M, 
medullary  corpuscle  unchanged ;  P.  central  plastid,  free  from  infiltration  ;  F,  capsule  of  fibrous 

connective  tissue.    Magnified  300  diameters. 

pulp,  mainly  the  arteries  and  capillaries,  transformed  into 
calcified  solid  rods  of  a  markedly  brown  color.  With  medium 
powers  of  the  microscope,  we  can  easily  ascertain  that  the 
majority  of  the  vessels  are  solidified,  only  a  few  being  choked 
with  red  blood-corpuscles.  Xo  doubt  the  primary  cause 
of  this  calcification  was  an  embolism  of  micrococci  of  an 
unknown  nature  in  the  arteries  and  capillaries,  which  did  not 
cause  pulpitis.  Next,  stagnation  of  the  blood  followed,  and  a 
number  of  red  blood-corpuscles  were  transformed  into  caky, 
vellow-brown    masses,   which  later  became    the   seat  of   calci- 


MORBID    ANATOMY    OF    ATROPHIES    AXD    DEGEXERATIONS.        423 

fication.  Some  of  the  vessels  look  homogeneous ;  others  eon- 
tain  a  number  of  cakj  masses,  freely  intermixed  with  micro- 
cocci. The  veins  have  escaped  calcification ;  only  a  few  exhibit 
clusters  of  diliusely-pigmented  cakes,  evidently  of  the  same 
origin  as  those  in  the  arteries  and  capillaries. 

Pulps  containing  a  larger  number  of  calcified  spieula?,  as  a 
rule,  exhibit  more  fibrous  connective  tissue  than  myxomatous. 
Invariably  around  the  calcified  masses  a  dense  layer  of  fibrous 
connective  tissue  has  formed,  ensheathing  the  calcified  masses. 
Where  these  masses  have  fallen  out  an  empty  fibrous  sac  is  left 
behind,  in  which  there  are  neither  endothelia,  so  characteristic 
of  blood-vessels,  nor  oblong  nuclei,  which  we  see  in  the  exter- 
nal perineurium  of  the  bundles  of  medullated  nerve-fibers. 
The  presence  of  this  envelope  may  convey  the  idea  (especially 
if  the  calcified  masses  are  elongated  and  appear  like  small 
lobulated  sausages)  that  an  obliteration  has  first  occurred  in 
the  blood-vessel  by  a  process  which  in  other  vascular  systems, 
mainly  that  of  the  lungs,  is  known  as  "  fatty  embolism."  The 
application  of  diflerent  reagents,  especially  osmic  acid,  has, 
however,  convinced  me  that  neither  of  these  formations  is  a  fat- 
embolism,  and  I  am  unable  to  observe  any  positive  connection 
between  the  blood-vessels  and  the  calcified  masses.  Sometimes 
it  looks  as  if  a  capillary  blood-vessel  were  attached  to  the  space 
containing  the  calcified  mass,  or  it  may  occur  that  a  capillary 
vessel  is  suddenly  dilated  like  a  small  aneurism,  and  in  this 
widened  portion  we  notice  pieces  of  a  calcified  mass.  The 
idea  that  the  plasma  of  the  blood  laden  with  lime-salts  accu- 
mulates in  the  capillaries  of  the  pulp,  and,  unable  to  escape 
behind,  deposits  its  lime-salts,  I  do  not  accept. 

b.  Ebumification  and  Ossification. — In  one  root  of  the  right 
lower  second  molar  of  a  physician  about  thirty-eight  years  old, 
circumscribed  chronic  pericementitis  eventuated  in  chronic 
plastic  pulpitis,  with  the  new  formation  of  fibrous  connective 
tissue,  and  the  formation  of  bone  along  the  wall  of  the  root- 
canal.  (See  Fig.  217.)  In  the  other  root  of  this  tooth  I  found 
most  of  the  bundles  of  the  medullated  nerves  calcified,  in  appear- 
ance similar  to  Fig.  226.  So  intense  was  the  pain  caused  by 
the  calcification  of  the  nerves,  that  the  tooth  had  to  be  removed. 
Ebumification  and  ossification  have  been  further  dwelt  upon  in 
Chapter  XXYI,  on  the  so-called  pulp-stones  (secondary  den- 
tine), to  which  the  reader  is  referred. 


424 


THE    AXATQMY    AXD    PATHOLOGY    OF    THE    TEETH. 


c.  Sclerosis. — A  peculiar  metamorphosis  is  sometimes  met 
with  in  the  pulp-tissue,  termed  sclerosis,  Avhich  is  closely  allied  to 
waxy  degeneration.  Whether  or  not  this  process  is  the  outcome  of 
pulpitis  I  am  unable  to  state.  This  much,  however,  is  certain^ 
that  the  unchanged  tissue  in  the  vicinity  of  a  sclerotic  portion  is 
not  infrequently  seen  inflamed.    (See  Fig.  223.)    Sclerosis  trans- 

FiG.  223. 


'jri??VY:"r?^''S7"'^'~'"~' '^'^'^.©f^^f ''■''''"' ■'"■^ 


Waxy  Degexeratiox  of  Pulp,  with  Acute  Pulpitis. 

W,  waxy  homogeneous  mass:  M,  M,  medullated  nerve-fibers,  broken  up  to  inflammatory  cor- 
puscles ;  1^,  vestiges  of  medullated  nerve;  P,  myxomatous  pulp-tissue,  slightly  inflamed  ;  ]V, 
medullated  nerve-fibers;  A,  acute  inflammation  of  pulp-tissue.    Magnified  500  diameters. 

forms  the  pulp-tissue  into  a  horny-looking,  nearly  homogeneous 
or  faintly  granular  mass,  holding  scanty  atrophied  nerves,  but 
no  blood-vessels.  It  differs  from  waxy  degeneration  in  so  much 
as  sclerotic  portions  are  hot  stained  by  ammoniacal  carmin 
solution,  which  is  invariably  the  case  in  waxy  degeneration. 


MORBID  AXATOMY  OF  ATROPHIES  AXD  DEGENERATIONS.   425 

d.  Reticular  Atrophy. — C.  \Vedl*  iirst  drew  attention  to  tliis 
condition.  Suc-li  atropliied  pulps  are  recognizable  with  the 
naked  eye  by  their  flattened,  shriveled  appearance  and  finely- 
indented  outer  surfaces.  Their  color  is  lighter  or  darker, 
2:rayish-ye]low  or  reddish-brown,  according  to  the  amount  of 


Fig.  224. 


-^5 


J: 


Calcareous  Embolisji  of  Capillaries  of  the  Pclp. 
R,  R,  incipient  reticular  atrophy;  C,  C,  arteries  and  capillaries  choked  with  emboli ;  V,  vein, 
holding  a  pigmented  eoagulum.    Magnified  10  diameters. 

necrotic  blood  present.  The  pulps  have  a  dry  appearance,  are 
brittle,  and  of  a  consistence  similar  to  parchment.  Wedl  at- 
tributes this  atrophy  to  a  withering  of  the  reticulated  connective- 
tissue  cells,  together  with  the  peripheral  blood-vessels  and  nerves. 

*  "  Pathology  of  the  Teeth,"  1872,  page  237. 


426 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


In  Fig.  224  this  process  is  illustrated  in  its  incipient  stage  at 
the  surface  of  both  the  coronal  and  root  portions.  This  pulp 
contains  a  number  of  blood-vessels,  mainl}'  arteries  and  capil- 
laries filled  with  calcareous  masses  of  a  yellow-brown  col  or  ^ 
which  have  obviously  taken  their  origin  from  coagulated  and 
disintegrated  blood.  The  nerve-bundles  are  conspicuous  by  their 
small  size. 

In  the  highest  degrees  of  this  atrophy  the  pulp-tissue  is  trans- 
formed into  a  myxomatous  reticulum,  lacking  lymph-corpuscles 


Tig.  225. 


Reticular  Atrophy  of  the  Pulp  (Wedl). 

^,  surface  of  pulp,  overspread  with  fine  oifshoots  ;  E,  myxomatous  reticulum,  with  nuclei  at  the- 
points  of  intersection  ;  N,  fibrous  bundles,  a  previous  bundle  of  nerves.  Magnified  500  diam- 
eters. 

in  its  meshes,  while  the  points  of  intersection  show  nuclei.  (See 
Fig.  225.)  The  cause  of  this  form  of  atrophy  is  a  serous  infil- 
tration of  the  pulp-tissue,  in  consequence  of  which  first  a 
hydropic  swelling,  followed  by  a  dissolution  of  the  constituent 
elements,  takes  place.  In  the  highest  degree  of  such  a  serous 
infiltration,  the  entire  pulp  may  be  dissolved.  In  rare  cases  we 
find  the  pulp-chamber  empty.  This  process  is  termed  "  dissolu- 
tion of  the  pulp." 


MORBID  ANATOMY  OF  ATROPHIES  AND  DEGENERATIONS.   427 

€.  Atrophy  of  the  Nerves  of  the    Pulp. — Atrophy   of   the 
medullated    nerves    appears    in    three   varieties, — i.e.,    simple 

Fig.  226. 


Atrophy  or  Medullated  Nerves  is  a  Living  Pulp  of  ax  Upper  Molar  of  a 
Person  Ttventt-five  Years  of  Age. 

B,  bundle  of  nerves;  M,  vestiges  of  medullary  corpuscles  ;  H,  nearly  homogeneous  sclerotic 
basis-substance.    Magnified  1200  diameters. 


atrophy,  transformation  into  fibrous  connective  tissue,  and  cal- 
cification.    In  sclerotic  pulps  we  frequently  meet  with  simple 


428 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


atrophy  of  medullated  nerves,  both  single  and  arranged  in 
bundles.  (See  Fig.  226.)  The  nerves  are  much  reduced  in 
their  bulk,  being  at  the  same  time  varicose   in  some  jjlaces, 


Fig.  227. 


Teansfoematiox  of  Bundles  of  Medullated  Nerves  into  Partly-Calcified  Bundles 

OF  Fibrous  Connective  Tissue.    Formation  of  Calcareous  Globule.    Crown 

Portion  of  Pulp. 

B,  B,  partly-calcified  bundles  of  fibrous  connective  tissue,  previous  medullated  nerves  ;  G, 
calcareous  globule,  embracing  a  number  of  fibrous  bundles;  C,  thoroughly -calcified  point  of 
globule,  directed  toward  the  surface  of  the  tooth ;  P,  P,  pulp-tissue  crowded  with  cocci.  Magni- 
fied 500  diameters. 

where  the  myelin  has  not  perished  altogether.  The  double 
contour  of  Schwann's  sheath  is  still  recognizable  even  in  the 
narrowest  portions  of  the  nerve-fibers,  where  myelin  does  not 


MORBID  ANATOMY  OF  ATROPHIES  AXD  DEGENERATIONS.   429 

exist.  I  have  been  unable  to  find  axis-cylinders  in  such  atrophic 
nerves,  not  even  in  their  transverse  sections.  The  internal  peri- 
neurium between  the  single  nerve-fibers  is  invariablv  auo'mented. 


Fig.  228. 


Calcified  Bundle  of  Medcllated  Nerves,    (From  Fig.  217.) 

N,  calcified  rod  of  a  previous  meduUated  nerve  ;  A,  calcified  amylaceous  corpuscle,  from  pre- 
vious myelin  ;  /,  inflamed  connective  tissue,  crowded  with  granules  of  lime-salts.  Magnified 
1200  diameters. 

Fibrous  degeneration  of  the  nerves  is  of  rare  occurrence,  as  it 
seems,  and  is  generally  combined  with  the  formation  of  calcar- 


430 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


ecus  globules.  (See  Fig.  227.)  An  example  of  this  degenera- 
tion is  also  depicted  in  the  figure  of  the  reticular  atrophy  of  the 
pulp.     The  bundles  of  medullated  nerves  become  transformed 


Fig.  229. 


Transformation  of  Buxdles  of  Medullated  Nerves  into  Paetly-Calcified  Bundles 

OF  Fibrous  Connective  Tissue.    Incipient  Formation  op  a  Calcareous  Globule. 

Root  Portion  op  Pulp. 

B,  B.  partly-calcified  bundles  of  fibrous  connective  tissue,  previous  medullated  nerves ;  G, 
-globule  made  up  of  finely-striated  basis-substance  ;  iV,  calcified  nucleus  of  globule  ;  R,  calcified 
rim  of  globule  toward  the  apex  of  the  root;  P,  P,  pulp-tissue,  crowded  with  cocci.  Magnified 
500  diameters. 


into  bundles  of  fibrous  connective  tissue,  which  latter  can  be 
traced  even  through  the  calcareous  globule.  The  myxomatous 
tissue  of  the  pulp  is  apparently  unchanged. 


MORBID  ANATOMY  OF  ATROPHIES  AND  DEGENERATIONS.   431 

Calcareous  degeneration  of  the  nerve-bundles  seems  to  invade 
llie  medullated  nerves  after  their  transformation  into  fibrous 
connective  tissue,  thoagh  this  preceding  stage  is  not  always 
traceable.  Fig.  228  shows  a  calcified  bundle  of  nerves,  from 
a  pulp  affected  with  chronic  purulent  inflammation,  abounding 
in  calcareous  deposits. 

A  combination  of  fibrous  and  calcareous  degeneration  is 
occasionally  met  with  in  pulps  otherwise  normal,  or  in  a  state 
of  slight  inflammation.  Fig.  229  shows  such  a  combination, 
and  is  valuable  for  demonstrating  the  devious  course  of  nerve- 
bundles  around  a  future  calcareous  globule,  which  for  the  present 
is  made  up  of  dense  concentric  layers  of  fibrous  connective  tissue, 
and  is  calcified  only  in  a  small  portion  of  its  .center. 

/.  Fatty  Degeneration. — According  to  Wedl,  fatty  degen- 
eration is  of  frequent  occurrence.  A  fatty  pulp  appears  cloudy, 
and  under  the  microscope  crowded  Tvith  fat-granules  in  all  its 
constituent  elements,  including  the  nerves.  Fatty  degeneration 
is  sometimes  observed  in  the  pulps  of  temporary  teeth,  while 
their  roots  are  undergoing  the  process  of  absorption.  Owing  to 
the  process  of  imbedding  our  pulps  in  celloidin,  made  liquid  by 
ether,  I  have  had  no  opportunity  to  observe  this  degeneration. 

g.  Pigmentation. — One  of  the  rarest  forms  of  degeneration 
of  the  pulp-tissue  is  pif/mentaUon.  In  Fig.  219  there  are  depicted 
clusters  of  pigment,  richest  in  one  horn  of  the  coronal  portion 
of  the  pulp.  These  clusters  appear  rust-brown  where  seen  in 
thin. layers,  and  jet-black  where  they  have  accumulated  in  heavy 
masses.  Unquestionably  this  pigmentation  is  the  outcome  of  a 
previous  hemorrhage,  the  more  explicable  since  the  pulp  under 
consideration,  besides  showing  calcareous  deposits,  is  aflfected  by 
chronic  purulent  pulpitis.  In  Fig.  22-4:  diffuse  pigmentation  of 
the  emboli  in  the  blood-vessels  is  observed,  likewise  arising  from 
the  coloring-matter  of  the  blood. 

h.  Colloid  Degeneration. — C.  Wedl  (I.e.)  has  observed  colloid 
corpuscles  in  the  pulp.  The  author  has  had  no  opportunity  to 
.see  such  corpuscles  in  specimens  of  his  own  collection. 


432  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

CHAPTER  XXXVIII. 

PERICEMEXTITIS  IN  ITS  CLINICAL  ASPECTS. 

In  regard  to  the  clapsification  of  the  diseases  of  the  root-mem- 
brane  and  the  alveolar  process,  man}''  systems  have  been  published ; 
but  to  find  one  which  from  both  pathological  and  clinical  point  of 
view  is  absolutely  satisfactory  has  proved  well-nigh  impossible. 

Albrecht*  was  the  first  to  give  the  subject  some  attention. 
He,  however,  classified  the  diseases  with  reference  to  their  clinical 
aspect  only.  Magitot,t  in  1882,  published  another  and  more 
extensive  classification  of  pericementitis,  adding  many  important 
points.  In  1885,  J.  Arkovy|  gave  quite  a  detailed  and  good 
system  of  the  diseases  of  the  pericementum  and  the  alveolar 
process.  Several  other  classifications  have  been  issued  since; 
but  neither  of  them  being  satisfactory  to  the  writer,  he  attempted 
to  formulate  a  new  one.  Although,  as  mentioned  above,  not 
free  from  objections  with  reference  to  its  clinical  aspect,  the 
author  hopes  it  may  meet  with  approval. 

Kon-Puridevi — 1.  Acute  marginal  pericementitis; 

2.  Acute  circumscribed  pericementitis; 

3.  Acute  apical  pericementitis; 

4.  Acute  difi:\ise  pericementitis; 

5.  Chronic    hyperplastic   partial    perice- 

mentitis; • 

6.  Chronic    hyperplastic    difiiise    perice- 

mentitis; 
Purulent. — 7.  Acute  apical  pericementitis; 

8.  Acute  diffase  pericementitis; 

9.  Chronic  marginal  pericementitis; 

10.  Chronic  circumscribed  pericementitis; 

11.  Chronic  apical  pericementitis; 

12.  Chronic  diftase  pericementitis. 
Serondary  Forms. — 13.  Chronic  alveolar  abscess; 

14.  Cementitis  and  eburnitis; 

15.  Periostitis,  osteitis,  and  osteomyelitis; 

16.  Lymphadenitis,  necrosis  of  the   jaw- 

bones, empyema  of  the  antrum. 

*  "  Die  Krankheiten  cler  Wurzelhaut  der  Zahne."     Berlin,  1860. 
t  "  Dictionnaire  Encyclopedique  des  Sciences  Medicales."    Par  Dechambre 
Paris,  1882. 

t  "Diao-nostik  der  Zahnkranliheiten."     Stutto;art,  1885. 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  433 

I.  Acute  Non-Purulent  Marginal  Pericementitis. — This  form 
of  pericementitis  occurs  around  the  necks  of  the  teeth,  and  is 
produced  by  chemical  or  mechanical  irritants.  The  chemical 
irritation  often  is  due  to  the  decomposition  of  food  left  between 
the  teeth,  or  forced  under  the  gum  in  mastication.  The  majority 
of  cases  of  this  form  of  pericementitis,  however,  are  caused  by 
mechanical  insults, — viz,  fine  pieces  of  bone,  a  part  of  a  tooth- 
pick, the  bristles  of  a  tooth-brush,  etc.,  which  have  entered  the 
pericementum ;  badly-fitting  clasps  of  artificial  dentures,  parti- 
cles of  oxyphosphate  cement  encroaching  upon  the  perice- 
mentum; crowns  and  bridges;  filling-materials  protruding 
above  the  cavities ;  pieces  of  rubber-dam  or  floss-silk  ligatures 
left  under  the  margin  of  the  gum  more  than  twenty-four  hours. 
Quite  frequently  this  disease  originates  from  salivary  calculus, 
manifesting  itself  by  a  bluish  ring  upon  the  gums  around  the 
necks  of  the  teeth.  The  inflammation  in  this  form  of  perice- 
mentitis seldom  extends  beyond  one-fourth  part  of  the  length  of 
the  root,  and  is  mostly  observed  in  the  pericementum  of  the 
approximal  surfaces  of  the  roots  of  the  teeth,  except  when  due  to 
an  accumulation  of  salivary  calculus,  in  which  case  it  is  mostly 
seen  upon  the  lingual  or  labial  surfaces,  though  sometimes 
encircling  the  entire  neck  of  the  tooth. 

Diagnosis. — Acute  non-purulent  marginal  pericementitis  is 
characterized  by  the  bright-red  color  of  the  gum  covering  the 
inflamed  pericementum.  The  gum  appears  more  or  less  de- 
tached from  the  neck  of  the  tooth,  and  an  instrument  may 
easily  be  passed  under  it.  An  instrument  coming  in  contact 
with  the  inflamed  pericementum  causes  pain  and  more  or  less 
hemorrhage.  Salivary  calculus,  as  before  mentioned,  causes  a 
bluish  color  of  the  gum  around  the  neck  of  the  tooth.  It  can 
readily  be  detected  by  an  instrument  which,  passed  over  salivary 
calculi,  will  impart  to  the  fingers  the  sensation  of  roughness 
characteristic  of  this  substance;  while,  in  absence  of  tartar, 
the  neck  of  the  tooth  appears  smooth.  The  tooth  usually  is 
somewhat  sensitive  upon  percussion  in  the  direction  of  the  in- 
flamed portion,  at  the  same  time  eliciting  a  somewhat  dull  sound. 

Subjective  Phenomena. — Acute  non-purulent  marginal  perice- 
mentitis seldom  produces  acute  pain,  but  rather  an  uneasy, 
annoying  sensation.  The  tooth  is  sensitive  to  mastication  and 
pressure,  and  usually  to  thermal  changes.  "When  produced  by 
salivary  calculi,  the  patient  scarcely  experiences  much  sensation, 

20 


434  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

except  iu  an  aggravation  of  the  inflammatory  process  by  particles 
of  food  lodged  under  the  gums. 

Differential  Diagnosis. — Although  in  the  majority  of  instances 
the  patient  is  able  to  localize  the  disease  in  the  root-membrane, 
there  is  a  possibility  of  confounding  acute  non-purulent  marginal 
pericementitis  with  irritation  of  the  pulp.  In  some  instances  we 
find  small,  deeply-seated  carious  cavities  under  the  margin  of 
the  gums,  which  likewise  may  produce  an  inflammation  of  the 
marginal  portion  of  the  gum.  In  most  cases,  however,  a  fine 
exploring  instrument  will  readily  enter  the  carious  cavity. 
Should  the  latter  be  situated  in  the  approximal  surfaces  of  one  of 
the  second  or  third  molars,  especially  in  short  teeth,  where  the 
necks  are  almost  as  large  as  the  crowns,  this  procedure  may 
become  diflicult. 

Prognosis. — After  the  removal  of  the  irritant  and  the  disin- 
fection of  the  mouth,  the  inflammation  in  the  gums  and  perice- 
mentum soon  abates,  unless  the  general  health  of  the  patient  be 
much  impaired,  in  which  case  the  inflammation  tends  to  become 
chronic. 

II.  Acute  Non-Purulent  Circumscribed  Pericementitis. — This 
form  of  pericementitis  mostly  involves  one  side  of  the  root,  or 
may  encircle  the  entire  root  about  its  middle,  without,  however, 
afi^ecting  the  apical  portion  of  the  pericementum.  The  area  of 
inflammation  seldom  extends  over  the  entire  root,  unless  the 
process  has  become  chronic. 

Arkovy,  who  gives  a  good  description  of  this  disease,  mentions 
two  forms  :  "  periodontitis  acuta  circumscripta  consecutiva,"  and 
"  periodontitis  acuta  circumscripta  idiopathica."  Since  both  forms 
are  identical,  except  in  their  origin,  I  shall  describe  them  under 
one  head.  Arkovy  furthermore  claims  that  acute  non-purulent 
circumscribed  pericementitis  arises  from  acute  total  pulpitis. 
My  specimens  and  clinical  observations  show,  on  the  contrary, 
that  the  pulpitis  is  the  result  of  the  pericementitis,  as  in  most 
instances  I  have  observed  a  new  formation  of  bone  or  secondary 
dentine  in  the  pulp-chamber,  corresponding  to  the  inflamed 
pericementum  on  the  outer  surface  of  the  root,  especially  in 
cases  due  to  constitutional  disturbances. 

Acute  non-purulent  circumscribed  pericementitis  may  origi- 
nate either  from  mechanical  violence  or  constitutional  disturb- 
ances. Among  the  former  I  will  enumerate  hard  biting,  or  a 
blow  applied  in  a  more  or  less  oblique  direction   to  the  root. 


PERICEMENTITIS    IX    ITS    CLINICAL    ASPECTS.  435 

Teeth  stanclino;  isolated  have  more  freedom  of  motion  than 
those  closely  approximated  by  others ;  thus  we  observe  acute 
non-purulent  circumscribed  pericementitis  mostly  in  such  teeth. 
J.  Foster  Flagg*  was  the  first  to  draw  attention  to  the  fact  that 
this  disease  sometimes  is  produced  by  constitutional  derange- 
ments, an  assertion  which  fully  concurs  with  my  own  observa- 
tions. 

Diagnosis. — Teeth  aiFected  by  acute  non-purulent  circum- 
scribed pericementitis  do  not  appear  looser  in  their  sockets  than 
the  other  teeth  in  the  mouth,  nor  longer  when  they  articulate. 
Since  the  disease  attacks  both  sound  and  decayed  teeth,  the  etiol- 
ogy must  be  carefully  considered  in  order  to  establish  a  diagnosis. 
It  mostly  lasts  from  one  to  three  days,  except  when  caused  by  con- 
stitutional disturbances,  in  which  case  chronicity  is  apt  to  ensue. 
The  teeth,  during  the  first  two  or  three  days  of  the  affection,  are 
but  little  sensitive  to  cold,  while  warmth  will  produce  no  altera- 
tion. The  main  characteristic  which  will  aid  us  in  the  diagnosis 
of  acute  non-purulent  circumscribed  pericementitis  is  percussion 
and  pressure  upon  the  crown  of  the  affected  tooth,  if  possible 
in  at  least  three  directions, — viz,  upon  the  grinding-surface, 
respectively  the  cutting-edge;  upon  the  labial,  respectively  the 
buccal  surface  ;  and  upon  the  lingual  surface.  When  the  peri- 
cementitis is  localized  mainly  or  exclusively  upon  the  lingual 
portion  of  the  root,  which  happens  in  the  majority  of  instances, 
percussion  upon  the  labial  respectively  the  buccal  surface  of  the 
tooth  will  yield  a  slightly  dull  sound  and  be  somewhat  sensitive. 
Percussion  or  pressure  upon  the  affected  tooth  in  the  other  two 
directions  mentioned  will  elicit  neither  pain  nor  dullness. 

Subjectice  Phenomena. — Acute  non-purulent  circumscribed 
pericementitis,  when  produced  by  mechanical  violence,  causes 
but  little  annoyance  to  the  patient,  except  when  pressure  or 
percussion  is  applied  in  the  manner  described  above.  When, 
however,  the  disease  has  originated  from  constitutional  derange- 
ments, the  subjective  symptoms  are  more  pronounced,  at  the 
same  time  affecting  two,  or  even  more,  teeth.  In  almost  all 
cases  I  have  seen,  I  have  noticed,  besides  the  acute  non-purulent 
circumscribed  pericementitis,  more  or  less  erosion,  and  an  acid 
reaction  of  the  saliva.  The  teeth  are  quite  sensitive  to  cold,  but 
I  could  not  ascertain  whether  this  was  due  to  the  pericementitis  or 
to  the  erosion.     Sometimes,  especially  in  teeth  standing  isolated, 

*  Dental  Cosmos,  1878. 


436  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

the  inflammatory  process  extends  to  the  neck  of  the  tooth,  and 
often  becomes  chronic  and  purulent,  presenting  the  features  of 
a  so-called  "blind  abscess"  (chronic  purulent  circumscribed 
pericementitis). 

Differential  Diagnosis. — The  only  disease  with  which  acute 
non-purulent  circumscribed  pericementitis  could  be  confounded 
is  chronic  purulent  circumscribed  pericementitis.  The 'latter  is 
characterized  by  the  soreness  upon  pressure  with  the  finger  on 
the  gum  over  the  root  of  the  affected  tooth,  whereby  a  small 
quantity  of  pus  may  be  seen  to  exude  at  the  neck  of  the  tooth. 
The  latter  symptom  is  never  observed  in  acute  non-purulent  cir- 
cumscribed pericementitis. 

The  -prognosis  of  teeth  affected  with  acute  non-purulent  cir- 
cumscribed pericementitis  as  the  result  of  mechanical  violence  is 
always  good ;  while,  on  the  contrary,  cases  depending  upon  con- 
stitutional trouble  sometimes ]become  chronic.  In  the  latter  in- 
stance the  pericementitis  induces  chronic  hyperplastic  pulpitis, 
followed  by  calcification  of  the  blood-vessels  and  nerves  of 
the  pulp,  usually  terminating  in  the  loss  of  the  tooth. 

III.  Acute  Non-Purulent  Apical  Pericementitis. — This  type  of 
pericementitis  is  of  frequent  occurrence,  and  is  mostly  produced 
by  pulpitis  and  by  mechanical  and  chemical  irritants.  Among 
the  forms  of  inflammation  of  the  pulp  that  may  induce  acute  non- 
purulent apical  pericementitis  are  the  following :  acute  total 
pulpitis,  acute  purulent  pulpitis,  chronic  total  hyperplasia  of  the 
pulp,  and  moist  gangrene.  The  last-named  disease,  if  rapidly 
progressing,  is  the  most  frequent  cause  of  acute  non-purulent 
apical  pericementitis,  which,  in  this  instance,  is  prone  to  involve 
the  entire  pericementum  of  the  tooth.  Apical  pericementitis 
may  be  induced  by  chemical  irritants,  such  as  filling-materials, 
which  during  the  process  of  filling  the  pulp-canal  have  been  forced 
through  the  apical  foramen  of  the  root  of  the  tooth.  The  same 
untoward  result  may  occur  when  chemical  irritants,  such  as  cor- 
rosive sublimate,  chloride  of  zinc,  pure  carbolic  acid,  iodine, 
etc.,  employed  in  the  disinfection  of  the  root-canal,  have  come 
in  contact  with  the  pericementum  through  the  apical  foramen. 
We  also  observe  this  form  of  pericementitis  after  extensive 
operations  in  restoring  large  portions  of  teeth  with  gold.  The 
protracted  or  too  severe  malleting  upon  a  tooth,  as  well  as  a 
protruding  filling,  a  crown,  a  bridge,  or  an  artificial  tooth  that 
causes  more  pressure  upon  its  antagonist  than   normal,  often 


PERICEMENTITIS    IX    ITS    CLINICAL    ASPECTS.     •  437 

produce  an  acute  non-purulent  apical  pericementitis.  This  may 
likewise  result  from  too  rapid  regulating,  wedging,  or  anything 
that  will  force  the  teeth  out  of  their  normal  position,  especially 
when  the  force  is  applied  in  the  direction  of  the  apex  of  the 
tooth. 

Diagnosis. — Acute  non-purulent  apical  pericementitis  is  easily 
recognized  by  slight  percussion,  either  with  an  instrument  or 
with  the  finger-nail.  In  teeth  possessing  but  one  root,  the  dull- 
ness as  well  as  the  soreness  elicited  upon  percussion  in  the  direc- 
tion of  the  apex  of  the  root  are  quite  marked ;  while  in  teeth 
having  two  or  three  roots,  both  dullness  and  soreness  upon  per- 
cussion are  not  so  pronounced,  unless  the  vibrations  are  produced 
in  the  direction  of  the  apex  of  the  affected  root.  The  same  will 
be  the  result  upon  pressure  which,  in  the  direction  of  the  apex 
of  the  affected  root,  produces  slight  pain,  while  when  applied 
laterally  to  the  affected  tooth  it  is  painless.  Acute  non-purulent 
apical  pericementitis  does  not  raise  the  teeth  out  of  their  sockets, 
consequently  they  are  not  looser  than  the  other  teeth  in  the 
mouth.  As  this  disease  frec|uently  occurs  in  teeth  which  either 
have  been  filled  or  contain  carious  cavities,  a  careful  examination 
must  be  made  in  regard  to  pulpitis,  or  the  particulars  in  regard 
to  the  filling  of  the  carious  cavity  or  the  pulp-canal  of  the  tooth. 

Subjective  Phenomena. — Acute  non-purulent  apical  pericemen- 
titis usually  becomes  noticeable  from  ten  to  twenty-four  hours 
after  the  irritation.  The  pain,  in  most  cases  starting  instanta- 
neously during  mastication,  is  localized  by  the  patient  in  the 
aiFected  tooth.  The  tooth  does  not  appear  elongated,  but  is 
sensitive  in  mastication.  The  pain  may  last  from  one  to  three 
days  after  the  removal  of  the  irritant. 

Diiferential  Diagnosis. — By  carefully  considering  the  etiology, 
tlie  diagnosis,  and  the  subjective  symptoms  of  acute  non-puru- 
lent apical  pericementitis,  it  is  barely  jjossible  to  confound  this 
disease  with  any  other  form  of  pericementitis.  It  may,  how- 
ever, sometimes  be  mistaken  for  chronic  partial  hyperplastic  or 
acute  purulent  apical  pericementitis. 

Chronic  partial  hyperplastic  pericementitis  is  characterized 
by  being  quite  sensitive  to  pressure  upon  the  gum  in  the  region 
of  the  apex  of  the  root  of  the  aifected  tooth,  which  pressure 
will  yield  negative  results  in  the  case  of  acute  non-purulent 
apical  pericementitis.  Acute  purulent  apical  pericementitis 
may  be  diflierentiated  by  the  rapidity  with  which  it  develops, 


438  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

the  severe  pulsating  pains,  as  well  as  the  elongation  of  the 
tooth,  all  of  which  phenomena  are  absent  in  acute  ??o?z-purulent 
apical  pericementitis. 

Prognosis. — According  to  the  origin  of  acute  non-purulent 
apical  pericementitis,  the  prognosis  of  this  disease  is  either 
quite  favorable  or  not.  If  the  disease  has  arisen  from  external 
violence,  such  as  too  heavy  or  too  long-continued  malleting, 
too  rapid  regulating,  fillings,  crowns,  or  artificial  teeth  left  too 
high,  or  wedging,  the  inflammation  upon  the  removal  of  the 
irritant  will  usuall}^  subside  in  from  one  to  three  days.  If,  on 
the  contrary,  acute  non-purulent  apical  pericementitis  is  pro- 
duced by  acute  purulent  pulpitis,  by  gangrene  of  the  pulp,  or 
by  filliug-materials  or  other  foreign  substances  pushed  through 
the  apical  foramen  of  the  root,  the  prognosis  becomes  unfavor- 
able. In  some  instances  the  disease  assumes  a  chronic  hyper- 
plastic character;  in  others  it  may  develop  into  an  acute  puru- 
lent apical  pericementitis,  the  prognosis  of  which  is  stated  in 
the  respective  paragraphs  of  this  chapter. 

IV.  Acute  Non-Purulent  Diffuse  Pericementitis. — This  disease 
usually  extends  over  the  greater  portion  of  the  root-membrane, 
although  we  seldom  find  the  cervical  portion  of  the  perice- 
mentum involved.  Arkovy  states  that  this  form  of  pericemen- 
titis is  accompanied  by  a  considerable  degree  of  cedema  of  the 
involved  portion  of  the  pericementum.  Acute  non-purulent 
diifuse  pericementitis  mostly  occurs  in  consequence  of  pulpitis, 
traumatism,  mechanical  or  chemical  irritation  at  the  apical  fora- 
men, and  sometimes  constitutional  derangements.  Of  the  dis- 
eases of  the  pulp,  only  those  of  a  quite  acute  character  will  pro- 
duce this  form  of  pericementitis, — viz,  acute  total  pulpitis,  or 
moist  gangrene.  In  a  traumatic  way  the  disease  may  be  pro- 
duced by  a  heavy  blow,  a  fall,  the  too  rapid  wedging  or  regu- 
lating of  the  teeth.  Sometimes  it  occurs  that  in  the  treating 
or  filling  of  pulp-canals  severe  chemical  irritants  are  pushed 
through  the  apical  foramen  of  the  root  or  enlarged  dentinal 
canaliculi ;  furthermore,  pieces  of  filling-materials,  either  metallic 
or  non-metallic,  or  a  broken  nerve-instrument  protruding  through 
the  apical  foramen,  may  lead  to  an  acute  non-purulent  diflruse 
pericementitis. 

Diagnosis. — As  we  always  notice  considerable  swelling  of  the 
pericementum,  the  afiected  tooth  will  be  found  quite  loose  in  its 
socket,  and  the  crown  raised  considerably  above  the  level  of  the 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  439 

Other  teeth.  Slight  percussion  upon  the  afi'ected  tooth  yields  a 
very  dull  sound ;  at  the  same  time  the  tooth  is  Cjuite  sensitive  to 
pressure,  especially  in  the  direction  toward  the  apex.  The  cor- 
responding gum  usually  exhibits  some  redness,  and  is  sensitive 
to  pressure,  without  indication  of  fluctuation.  When  this  dis- 
ease occurs  in  teeth  with  living  pulps,  an  irrigation  of  cold 
water  produces  pain,  which  symptom  always  calls  for  a  careful 
examination  of  the  pulp-chamber. 

Subjective  Phenomena. — The  pain  of  acute  non-purulent  diffuse 
pericementitis  develops  gradually  about  twenty  to  thirty  hours 
after  the  irritation,  at  least  in  cases  originating  from  mechanical 
or  chemical  violence.  The  pain  in  the  latter  instances  is  acute 
and  drawing.  When,  however,  the  disease  originates  from  acute 
total  pulpitis  or  gangrene  of  the  pulp,  the  patient  complains  of 
severe  throbbing  pain,  not  only  in  the  aftected  part,  but  over  the 
whole  side  of  the  face.  As  the  tooth  is  raised  out  of  its  socket 
considerably  above  the  level  of  the  other  teeth,  mastication,  or 
even  the  closure  of  the  mouth,  is  rendered  impossible.  This 
state  may  continue  for  three  or  four  days,  and  sometimes  may 
last  a  week,  when  the  inflammation  either  gradually  abates  or 
becomes  chronic.  The  pain  usually  is  much  more  severe  toward 
evening,  especially  when  the  patient  occupies  a  recumbent  posi- 
tion, or  after  taking  alcoholic  stimulants  or  active  bodily  exercise. 

Differential  Diagnosis. — Acute  non-purulent  diffuse  perice- 
mentitis may  be  confounded  with  acute  or  chronic  purulent 
diffuse  pericementitis.  Acute  purulent  dift'use  pericementitis  is 
principally  characterized,  in  contradistinction  to  acute  non- 
purulent difiuse  pericementitis,  by  the  former  never  being  sen- 
sitive to  cold  applications;  the  presence  of  fever;  besides,  upon 
slight  pressure  on  the  gums  pus  will  be  eliminated.  The  gums 
in  the  purulent  form  are  seldom  attached  tightly  to  the  neck  of 
the  tooth ;  they  are  considerably  swollen,  and  at  the  same  time 
fluctuating. 

Chronic  purulent  diffuse  pericementitis  principally  differs 
from  the  acute  non-purulent  diffuse  form  in  the  character  of 
the  subjective  phenomena,  which  in  a  chronic  disease  are  never 
intense. 

The  prognosis  of  acute  non-purulent  diffuse  pericementitis,  in 
the  majority  of  instances,  is  favorable  for  the  preservation  of 
the  tooth,  although  in  cases  where  chemical  irritants  or  foreign 
bodies  pushed  through  the  apical  foramen  have  produced  the 


440  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

inflammation,  the  prognosis  is  not  so  favorable.  In  the  latter 
instances,  as  well  as  in  those  originated  from  gangrene  of  the 
pulp,  an  invasion  of  strepto-  and  staphylococci  takes  place,  fol- 
lowed by  purulent  pericementitis. 

V.  Chronic  Hyperplastic  Partial  Pericementitis. — Under  this 
head  I  propose  to  classify  the  growths  of  the  pericementum 
occurring  around  the  cervical  portion  and  sometimes  lodging  in 
carious  cavities  about  the  necks  of  the  teeth.  In  this  situation 
they  may  easily  be  confounded  with  a  hyperplastic  pulp,  espe- 
cially when  in  a  largely-decayed  molar  the  pericementum  has 
grown  through  a  perforation  at  the  bifurcation  of  the  roots. 
This  disease,  however,  is  not  exclusively  found  in  carious  teeth, 
but  also  in  those  with  apparently  sound  crowns.  The  etiology 
is  not  perfectly  clear  in  all  cases.  The  author,  however,  has- 
frequently  found  it  to  be  the  result  of  chronic  purulent  marginal 
pericementitis  (pyorrhoea  alveolaris). 

Diagnosis. — In  most  instances  chronic  hyperplastic  partial 
pericementitis  is  readily  recognized  by  the  presence  of  granula- 
tion-tissue. The  latter  appears  knob-shaped  at  one  side  of  the 
neck  portion  of  the  pericementum  in  varying  sizes.  "When 
these  growths  occupy  carious  cavities,  they  seldom  surpass  the 
size  of  the  head  of  a  pin  or  that  of  a  pea.  Exceptionally  w^e  meet 
with  granulations  the  size  of  a  walnut  or  even  larger,  mostly 
occupying  the  labial,  respectively  buccal  surface  of  otherwise 
sound  teeth.  The  tumor  in  the  latter  cases  is  attached  by  means 
of  a  pedicle  and  lobulated  upon  its  upper  surface,  while  the 
lower  one  resting  upon  the  gum  usually  is  smooth.  The  so- 
called  granulomata  are  richly  supplied  with  capillary  blood- 
vessels, and  therefore  bleed  profusely  when  wounded.  The  teeth 
are  not  looser  in  their  sockets  than  the  other  teeth  in  the  mouth,. 
and  percussion  elicits  a  dull  sound  only  in  the  direction  of  the 
diseased  portion  of  the  pericementum. 

Subjective  Phenomena. — Chronic  hyperplastic  partial  perice- 
mentitis does  not  produce  pain  as  such,  except  when  the  growth 
becomes  irritated  in  mastication  or  by  exposure  to  pronounced 
thermal  changes. 

Differential  Diagnosis. — When  chronic  hyperplastic  partial 
pericementitis  occurs  in  teeth  the  crowns  of  w^hich  are  largely 
decayed  at  their  cervical  portion  as  above  mentioned,  it  may 
easily  be  confounded  with  granuloma  of  the  gum  or  partial 
hyperplasia  of  the  pulp.     In  such  instances  the  granuloma  of 


PERICEMENTITIS    IX    ITS    CLINICAL    ASPECTS.  441 

the  pericementum  grows  into  the  carious  cavity,  and  sometimes, 
in  devitalized  teeth,  may  even  occupy  the  pulp-chamber.  A 
thorough  examination  is  not  always  possible  at  once,  since  the 
granulations  of  the  gum  and  the  pulp,  as  well  as  those  of  the 
pericementum,  bleed  profusely.  It  is  advisable  to  insert  a  piece 
of  cotton,  saturated  with  pure  carbolic  acid,  into  the  cavity  of 
the  tooth,  which  after  twenty-four  hours  will  enable  us  to  make 
a  clear  diagnosis.  When  chronic  hyperplastic  partial  perice- 
mentitis occurs  in  teeth  in  the  early  stage  of  pyorrhoea  alveo- 
laris,  the  disease  under  consideration  is  easily  recognizable. 
Here  it  sometimes  happens  that  the  granulations  have  destroyed 
small  portions  in  the  neck  or  the  root,  which  latter  appear  in  the 
form  of  cup-shaped  excavations. 

Prognosis. — So  long  as  chronic  hyperplastic  partial  perice- 
mentitis occurs  in  places  accessible  to  removal  of  the  granuloma, 
and  prevention  of  its  recurrence  by  the  application  of  strong 
escharotics,  the  tooth  need  not  be  sacrificed.  T\"hen,  on  the  con- 
trary, the  granulations  have  absorbed  portions  of  the  root,  the 
prognosis  becomes  doubtful.  The  sharp  edges  of  the  excavations 
on  the  root  irritate  the  pericementum  even  after  the  granulations 
have  been  destroyed,  and  usually  give  rise  to  an  incessant  new 
formation  thereof. 

VI.  Chronic  Hyperplastic  Diffuse  Pericementitis. — This  form 
of  pericementitis  embraces  the  new  formations  occurring  in  the 
pericementum  below  the  margin  of  the  alveolus.  They  mostly 
are  built  up  of  granulation-tissue,  gradually  absorbing  the  roots  of 
the  teeth  as  well  as  the  alveolus  of  the  jaw-bone.  This  form  of 
pericementitis  predominates  in  teeth  of  young  patients,  especially 
when  the  roots  were  not  fully  formed  at  the  time  of  death  of 
the  pulp.  We  also  notice  it  in  teeth  the  pulp-canals  of  which 
have  been  filled  with  gold  wire.  ISo  pus  is  noticed  in  hyper- 
plastic pericementitis  unless  it  is  accompanied  by  a  purulent 
form  of  pericementitis. 

The  diagnosis  of  chronic  hyperplastic  diffuse  pericementitis 
cannot  always  be  established  with  certainty.  Although  such 
teeth  are  loose,  and  appear  considerably  elongated,  the  gums 
around  their  necks  may  be  normally  attached,  and  a  probe  can- 
not be  easily  introduced  along  the  root  of  the  tooth.  When, 
however,  the  gum  encircling  the  neck  has  lost  its  attachment  to 
the  tooth,  the  granulomata  in  some  instances  can  be  distinctly 
felt  by  means  of  a  probe.     The  latter  feature  mostly  prevails 


442  THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

in  diffuse  cases :  when  the  granuloma  involves  only  the  apical 
portion  of  the  pericementum,  an  examination  by  the  probe  is 
impossible.  The  gum  in  the  vicinity  of  the  affected  root  usually 
appears  almost  normal. 

SabjecHve  Phenomena. — Chronic  hyperplastic  pericementitis 
seldom  causes  pain  or  much  discomfort  to  the  patient.  Teeth 
thus  affected  are  quite  loose  and  somewhat  elongated,  although 
the  surrounding  gum  shows  little  or  no  signs  of  inflammation. 
Pressure  upon  the  tooth  in  the  direction  of  the  apex  of  the  root 
usually  is  painful. 

Differential  Diagnosis. — Chronic  non-purulent  diffuse  perice- 
mentitis may  easily  be  confounded  with  chronic  purulent  apical, 
as  well  as  with  chronic  purulent  dift'use  pericementitis.  In  fact, 
in  both  of  these  forms  where  the  inflammatory  process  has  lasted 
for  some  time,  we  often  observe  new  formations  of  fibrous  con- 
nective tissue  and  bone-tissue  in  the  vicinity  of  the  inflamed 
pericementum.  The  characteristic  features  of  the  disease  in 
question  are  not  well  marked. 

The  2^'^ognosis  of  teeth  affected  with  chronic  non-purulent 
diffuse  pericementitis  is  always  bad,  since  the  root  gradually 
becomes  absorbed,  and  the  tooth,  unless  extracted,  in  course  of 
time  falls  out. 

VII.  Acute  Purulent  Apical  Pericementitis. — As  every  puru- 
lent inflammation  depends  upon  an  infection  of  the  tissue  with 
staphylococci,  sometimes  combined  with  streptococci,  acute  puru- 
lent partial  pericementitis  never  occurs  unless  an  infection  with 
the  above-named  micro-organisms  has  taken  place.  The  disease 
under  consideration  frequently  is  induced  by  gangrene  of  the  pulp; 
also  by  acute  or  chronic  purulent  total  pulpitis ;  eventually  by 
septic  nerve-instruments  introduced  into  the  pulp-canal  or 
through  the  apical  foramen.  With  regard  to  the  aseptic  condi- 
tion of  instruments,  I  would  advise  the  utmost  care;  although  I 
must  admit  that  an  absolute  aseptic  treatment  in  the  mouth  is 
next  to  an  impossibility,  even  though  the  rubber-dam  be  applied. 
Bacteria  are  organisms  so  minute  that  they  can  only  be  detected 
b}-  the  microscope  with  a  magnifying  power  of  at  least  600 
diameters.  The  human  mouth  is  crowded  with  micro-organ- 
isms, and  they  will  adhere  to  everything  coming  in  contact  with 
it.  Our  fingers  will  transfer  them  to  the  handles  of  instruments, 
the  hand-piece  of  the  dental  engine,  napkins,  towels,  cotton,  etc. 
Bacteria  may  even  enter  a  pulp-canal  although  the  instrument 


PERICEMENTITIS    IX    ITS    CLINICAL    ASPECTS.  443 

■used  was  sterilized,  and  the  hands  after  the  application  of  the 
rubber-dam  have  been  thoroughly  washed.  I  am  convinced 
that  everything  in  the  office  coming  in  contact  with  the  fingers 
of  the  operator  is  more  or  less  infected  with  micro-organisms. 
If,  therefore,  a  nerve-instrument  touches  a  napkin,  a  towel,  the 
rubber-dam,  or  anything  which  has  been  in  contact  with  our 
hands,  before  they  were  thoroughly  washed  again,  an  infection 
of  the  pericementum  may  be  the  result.  It  is  evident  that  an 
aseptic  treatment  of  a  pulp-canal  without  the  application  of  the 
rubber-clam  to  the  affected  tooth  is  impossible.  This  fact  no 
doubt  explains  the  origin  of  many  occult  cases  of  acute  purulent 
apical  pericementitis. 

Diagnosis. — Acute  purulent  apical  pericementitis  never  occurs 
unless  the  pulp  of  the  tooth  be  affected  by  total  purulent  inflam- 
mation, by  gangrene,  or  in  a  devitalized  tooth.  The  gum 
around  the  root  of  the  tooth  usupJly  is  but  little  swollen  or  altered 
in  color,  and  unyielding,  though  somewhat  painful  to  pressure. 
The  tooth  appears  but  little  higher,  and  is  only  partially  sensi- 
tive in  mastication.  Slight  percussion  upon  the  tooth,  especially 
in  a  labio-lingual  direction,  is  quite  painful,  and  elicits  a  distinctly 
dull  sound.  Such  teeth  are  seldom  looser  than  the  other  teeth 
in  the  mouth. 

Subjective  Phenomena. — When  a  tooth  becomes  affected  with 
acute  purulent  apical  pericementitis,  the  patient  notices  soreness 
of  the  tooth  about  eight  to  twelve  hours  after  the  infection  of 
the  pericementum.  This  is  followed  by  gradually  increasing 
pain,  which  after  about  twenty-four  hours  becomes  severe  and 
of  a  pulsating  character.  The  tooth  now  is  extremely  sensitive 
to  cold,  and  even  the  inhalation  of  cold  air  produces  pain.  The 
affected  side  of  the  mouth  feels  quite  hot,  especially  the  gum  in 
the  neighborhood  of  the  root  of  the  diseased  tooth.  Toward 
evening  the  patient  usually  is  attacked  by  fever,  the  severity  of 
which,  however,  depends  upon  his  constitution.  The  pains  are 
much  aggravated  in  the  recumbent  position,  by  active  bodily 
exercise,  or  alcoholic  stimulants. 

Differential  Diagnosis. — Acute  purulent  apical  pericementitis 
may  be  confounded  with  acute  non-purulent  partial  pericemen- 
titis, although  the  pulsating  character  of  the  pain  always  present 
in  the  former  disease  is  never  noticed  in  pericementitis,  not 
terminating  in  suppuration. 

The  prognosis  of  teeth  attacked  by  an  acute  purulent  apical 


444  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

pericementitis,  as  a  rule,  is  favorable,  although  rauch  depending- 
upon  the  constitution  and  the  age  of  the  patient,  the  shape  of 
the  pulp-canal,  and  the  position  of  the  tooth.  Whenever  the 
practitioner  is  able  to  obtain  entrance  through  the  apical  fora- 
men, by  means  of  a  fine  broach,  into  the  abscess,  and  thereby 
evacuate  the  pus,  the  pain  will  almost  instantly  cease.  The 
tooth  and  pulp-canal,  after  proper  treatment,  may  then  be  filled, 
which  when  successfully  accomplished  will  preserve  the  tooth. 

VIII.  Acute  Purulent  Diffuse  Pericementitis.— This  disease 
is  almost  invariably  the  outcome  of  the  one  before  described, 
its  etiology  being  similar. 

Diagnosis. —  A  tooth  affected  with  acute  purulent  diffuse  peri- 
cementitis is  extremely  sensitive  to  the  touch  with  the  finger, 
or  even  the  tongue.  It  is  quite  loose  in  its  socket,  and  appears 
considerably  elongated  above  the  level  of  the  other  teeth,  so 
much  so  that  the  patient  is  unable  to  eat  or  even  to  close  his 
mouth.  The  corresponding  cheek  or  lip  becomes  cedematous, 
producing  a  marked  disfigurement,  and  sometimes  complete 
closure  of  the  eyelids.  The  gum  in  the  vicinity  of  the  affected 
tooth  always  is  swollen,  and  painful  to  pressure  with  the  point 
of  a  finger.  In  some  instances,  upon  pressure  more  or  less  pus 
will  be  eliminated  around  the  cervical  portion  of  the  tooth. 
According  to  the  severity  of  the  process  the  inflammation  is 
imparted  to  the  alveoli  and  the  pericementum  of  the  neighbor- 
ing teeth,  to  such  an  extent  that  only  the  characteristic  color 
of  the  dead  tooth  will  indicate  the  original  seat  of  the  abscess. 
Thermal  changes,  especially  cold  applications,  are  quite  pain- 
ful. Slight  percussion,  which  ought  to  be  applied  gently,  is 
extremely  painful,  and  produces  a  dull  sound.  Should  the 
neighboring  alveoli  be  involved  in  the  inflammatory  focus,  the 
tooth  which  is  the  original  seat  of  the  pericementitis  will 
always  elicit  the  comparatively  dullest  sound. 

Subjective  Phenomena. — The  pain  before  the  appearance  of 
the  oedema  caused  by  acute  purulent  diffuse  pericementitis,  is 
stated  to  be  among  the  severest  of  human  sufferings.  Its 
character  is  pulsating,  affecting  the  whole  side  of  the  face,  and 
is  materially  increased  by  the  recumbent  position,  by  bodily 
exercise,  and  alcoholic  beverages.  Although  there  are  no 
intermissions  of  pain,  it  usually  is  worse  toward  evening,  or  at 
night.  The  pain  steadily  increases  from  hour  to  hour,  until  it 
becomes  almost  unbearable.     A  severe  chill  indicates  that  pus 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  445 

lias  formed.  With  still  increasing  pain  fever  sets  in;  the 
patient's  temperature  is  elevated,  the  pulse  accelerated,  the 
appetite  lost,  and  the  tongue  becomes  thickly  coated.  The 
suffering  continues  from  one  to  five  days,  when  at  once  an 
oedema  of  the  face  makes  its  appearance,  whereby  the  patient 
is  relieved,  the  pain  now  assuming  a  more  or  less  dull  and 
intermittent  character. 

Differential  Diagnosis. — Acute  purulent  diffuse  pericementitis 
may  be  confounded  with  acute  diffuse  non-purulent,  or  chronic 
purulent  diffuse  pericementitis.  The  principal  characteristic 
feature  of  acute  purulent  diffuse  pericementitis  is  its  initiation 
by  a  chill  followed  by  fever,  which  never  occurs  in  the  non- 
purulent form. 

Chronic  purulent  diffuse  pericementitis  may  easily  be  dis- 
criminated fi-om  an  acute  one  by  the  character  of  the  pain  and 
the  absence  of  fever.  In  an  acute  inflammation  the  pains  are 
severe,  pulsatiug,  and  steadily  increasing,  while  in  chronic 
inflammation  the  pain  is  not  severe,  of  a  more  intermittent  and 
drawing  character. 

The  ijrognosis  of  teeth  affected  "with  acute  purulent  diffuse 
pericementitis  is  almost  as  good  as  that  of  teeth  attacked  by 
the  apical  form. 

The  same  rule  is  applicable  in  both  instances, — ^'iz,  when- 
ever we  are  able  to  evacuate  the  pus  from  the  alveolus,  either 
by  incision  through  the  gums  or  by  means  of  a  fine  broach 
through  the  X3ulp-canal,  or  both  ways  combined,  the  tooth 
may  be  saved.  To  accomplish  this,  however,  the  pulp-canal 
as  well  as  the  tooth,  after  the  disappearance  of  the  abscess, 
must  be  thoroughly  disinfected  and  filled.  The  greatest  obsta- 
cles to  treating  such  a  tooth  are  both  its  looseness  and  the  pain 
produced  by  the  opening  of  the  palp-canal.  This,  nevertheless, 
in  most  instances  can  be  accomplished  by  fastening  the  tooth  to 
a  ligature  and  pulling  it  by  the  string  against  the  drill.  In 
severe  cases,  the  tooth,  besides  being  ligated,  must  be  held  with 
two  fingers  by  an  assistant,  while  the  canal  is  opened  by  a 
drill. 

IX.  Chronic  Purulent  Marginal  Pericementitis,  so-called 
"Pyorrhoea  Alveolaris." — This  disease  has  also  been  termed 
"pyorrhoea  alveolo,"  Toirac  by  Desirabode;  "  cemento-perios- 
titis,"  by  Magitot;  "  gingivitis  expulsiva,"  by  Marchal  de  Calve; 
"alveolitis  infectiosa,"  by  A.  Witzel;  -'Blennorrhoe  der  Alveo- 


446      THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH, 

len,"  by  Steinberger ;  and  Eiggs's  Disease,  The  last  name  was 
coined  in  honor  of  Dr.  Riggs,  who  was  the  first  to  give  this 
disease  special  attention. 

In  regard  to  the  etiolosrv  of  the  disease  under  consideration, 
few  positive  facts  are  known ;  but  hypothetical  speculations 
about  it  are  quite  abundant.  Prior  to  the  time  of  Riggs  (1867), 
pyorrhoea  alveolaris  was  believed  to  be  a  disease  of  the  gums. 
Riggs  himself  was  of  the  opinion  that  the  disease  was  a  necrotic 
condition  of  the  alveolar  border.  In  1873  Magitot  proved  that 
the  trouble  was  situated  in  the  pericementum.  C.  Tomes  first 
made  the  statement  that  pyorrhoea  alveolaris  was  not  due  to 
deposits  of  salivary  calculi,  which,  up  to  his  time,  was  believed 
to  be  the  cause.  Tomes  furthermore  called  attention  to  the  fact 
that  tartar  is  of  secondary  importance,  and  in  many  cases  no  cal- 
culi are  present.  Since  that  time  much  has  been  said  and  written 
on  the  subject,  without,  however,  advancing  anything  of  impor- 
tance, except  that  many  practitioners  agreed  in  that  the  disease 
was  not  primarily  due  to  a  deposition  of  salivary  calculi,  but 
rather  to  systemic  derangements.  J,  Arkovy  calls  this  disease 
"  caries  alveolaris,"  and  maintains  that  its  origin  is  a  necrotic 
process  in  the  margin  of  the  alveolus,  which  in  later  stages  is 
transferred  to  the  pericementum  and  cementum  of  the  tooth. 
C.  ]Sr.  Peirce,  in  a  paper  read  before  the  'New  York  Odontological 
Society,  ISTovember,  1893,*  expressed  the  view  that  pyorrhoea 
alveolaris  is  principally  due  to  a  gouty  diathesis  of  the  system, 
and  defines  two  forms  of  this  disease.  He  says,  "  In  one  form 
of  pericementitis  the  origin  of  the  calcic  salt  is  the  saliva,  and 
in  the  other  form  the  blood.  The  former  I  shall  designate  a 
pti/alogenic  calcic  pericementitis,  expressive  of  the  idea  that  in  its 
origin  it  is  local,  peripheral,  and  salivary.  The  latter  I  shall 
designate  as  hcematogenic  calcic  pericementitis,  expressive  of 
the  idea  that  in  its  origin  it  is  constitutional,  central,  and  asso- 
ciated with  some  modifications  of  the  normal  composites  of  the 
blood-plasma. 

"  Calcic  pericementitis  may  have  its  origin  at  the  gingival  borders, 
the  tartar  acting  as  a  local  and  mechanical  irritant,  luith  the  train  of 
concomitant  evils,  such  as  irritation,  inflammation,  formation  of  pus, 
and  absorption  of  gum  and  alveolar  process. 

"  We  have  three  distinct,  abnormal  conditions  affecting  the  gums, 
pericemental  or   alveolo-cemental  membrane,   and  cdveolar  process. 

*  The  International  Dental  Journal^  1894. 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  447 

Thejirst  is  gum  inflammation  and  destruction,  caused  hy  a  mechanical 
irritant.  Second,  inflammation  of  the  gingival  borders  without  the 
presence  of  tartar.  The  third  is  a  pericemental  irritation  commencing 
at  or  near  the  apical  extremity  of  the  root,  due  to  the  iwesence  of  some 
morbid  comjMsite  of  the  blood,  exuded  uith  the  plasma  and  inflltrating 
the  alveolo-cemental  membrane,  and  frequently  deposited  or  precijntated 
upon  the  root  of  the  tooth  near  its  apex.  This  latter  1  designated  true 
pyorrhoea  alveolaris,  or  hamaiogenic  pericementitis,  and  so  intimately  is 
it  associated  with  some  other  local  manifestcdion  of  a  gouty  diathesis, 
that  I  have  believed  and  do  now  believe  it  to  be  but  another  local 
expression  of  that  systemic  condition." 

While  the  views  of  Peirce  have  many  followers,  among  whom 
are  Edwin  T.  Darby,  S.  G.  Perry,  K.  R.  Andrews,  A.  P.  Bru- 
baker,  and  others,  the  contradictory  opinions  seem  to  be  just 
as  strong,  as  expressed  by  S.  H.  Guilford,  M.  L.  Rhein,  James 
Truman,  R.  Ottolengui,  G.  S.  Allan,  as  well  as  the  writer,  and 
others.  It  cannot  be  denied  that  a  superabundance  of  uric  acid 
in  the  system  may 'assist  in  producing  pyorrhoea  alveolaris;  but 
it  will  not  exert  more  influence  in  this  direction  than  consump- 
tion, anaemia,  nephritis,  hepatitis,  diabetes,  arthritis,  syphilis, 
typhoid,  chronic  diseases  of  the  nervous  system,  etc.,  which  are 
often  found  associated  with  pyorrhoea  alveolaris.  Furthermore, 
it  is  an  established  fact  that  sometimes  uric  acid  is  present  in 
the  system  without  producing  either  gout  or  rheumatism.  We 
must  therefore  admit  that  the  cause  of  the  disease  under  con- 
sideration principally  is  a  more  or  less  chronic  general  ailment, 
and  not  due  to  any  particular  form.  At  the  same  time,  we  meet 
with  many  cases  of  pyorrhoea  alveolaris  which  can  be  attributed 
to  nothing  but  heredity.  The  disease  is  mostly  limited  to  middle 
age,  although  exceptionally  we  see  it  in  persons  under  twenty 
years. 

Diagnosis. — Chronic  purulent  marginal  pericementitis  begins 
as  an  acute  or  a  subacute  inflammation  in  the  cervical  portion, 
soon  becoming  purulent  and  afterward  chronic.  In  the  early 
stages  the  gum  is  yet  of  a  normal  color,  and  detached  from  the 
neck  of  the  tooth  only  in  a  small  area, — as  a  rule,  upon  the  labial 
surface.  Salivary  calculi  seldom  are  seen  in  those  places  where 
the  gum  is  found  detached  from  the  neck  of  the  tooth,  although 
it  may  be  present  upon  the  lingual  or  the  approximal  surfaces  of 
the  teeth.  Exceptionally  we  meet  with  patients  sufiering  from 
pyorrhoea  alveolaris,  in  consequence  of  rheumatism,  who  have  an 


448  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

abundant  accumulation  of  calculi  above  the  gum-margin.  Some- 
times we  pieet  with  pyorrhoea  alveolaris  in  which  the  calculary 
deposit  encircles  the  entire  necks  of  the  teeth;  but  in  these 
instances  the  tartar  had  formed  previously  to  the  development 
of  the  disease  under  consideration.  The  deposits  below  the 
gum-margin  which  later  accumulate  upon  the  roots  of  the  affected 
teeth  usually  have  been  called  "  seruminal  tartar,"  in  contradis- 
tinction to  that  found  upon  the  teeth  above  the  gum-margin. 
The  former  deposits  are  of  a  dark-brown  or  black  color,  and,  as 
the  disease  progresses,  gradually  extend  toward  the  apex  of  the' 
root.  In  some  instances  the  middle  portion  of  the  pericemen- 
tum of  the  root  remains  intact,  and  at  the  first  glance  it  appears 
as  though  the  deposit  at  the  apex  of  the  tooth  were  in  no  con- 
nection with  that  found  upon  the  neck.  Closer  examination 
with  a  magnifying  lens,  however,  shows  that  the  deposits  in  one 
or  more  narrow  routes  have  obtained  access  to  the  apical  por- 
tion. In  the  incipient  stage  of  the  disease  the  affected  teeth  are 
not  looser  than  the  others  in  the  mouth,  and  the  only  symptom 
indicative  of  pyorrhoea  alveolaris  is  the  presence  of  pus  upon 
pressure  around  the  neck  of  the  tooth.  At  first  the  quantity  of 
pus  eliminated  is  small,  seldom  more  than  about  one  drop  in 
ten  or  twelve  hours.  The  pus  can  be  best  exhibited  by  pressure 
upon  the  gum,  gradually  extending  toward  the  cutting-edge, 
respectively  the  grinding-surface  of  the  tooth.  In  advanced 
stages,  however,  the  pus  may  flow  continually  from  the  sockets, 
causing  a  peculiar  odor  of  the  breath  of  the  patient.  With  the 
progress  of  the  disease  the  pericementum  is  destroyed  by  degrees, 
and  the  so-called  pocket  between  the  gum  and  the  neck  of  the 
tooth  becomes  deeper.  In  some  instances  we  notice  the  margin 
of  the  gum  to  be  thin  and  sharp ;  in  others  the  gum  appears 
thick  and  almost  hypertrophied,  which  fact  seems  to  have  little 
to  do  with  the  stage  of  the  disease,  as  both  conditions  are 
noticed  in  deep  as  well  as  in  shallow  pockets.  As  the  destruc- 
tion of  the  pericementum  advances,  the  gum  recedes  from  the 
necks  of  the  teeth,  especially  the  labial  surfaces,  which,  as  a 
rule,  become  sensitive  to  thermal  changes,  particularly  to  cold. 
The  teeth  by  degrees  lose  their  firm  hold  in  the  alveolus,  due  to 
the  absorption  of  the  cementum  and  the  socket.  This  enables 
us  to  introduce  a  probe,  sometimes  more  than  half-way  between 
the  alveolus  and  the  root  of  the  tooth,  without  pain.  Pyorrhoea 
alveolaris  is  not  uncommon  in  front  teeth  which  have  lost  their 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  449 

X)roper  antagonism,  especially  when  either  the  upper  or  the 
lower  jaw  protrudes.  As  the  disease  proceeds  toward  the  apex 
of  the  root  the  socket  is  destroyed,  sometimes  only  on  one 
side,  but  often  in  the  entire  extent  of  the  root  of  the  tooth.  In 
such  instances  the  pulp  of  the  tooth  often  becomes  devitalized, 
mostly  without  the  knowledge  of  the  patient.  The  affected 
teeth  seldom  are  discolored,  and  I  have  seen  instances  where 
transillumination  gave  but  negative  results.  When  the  inflam- 
matory process  has  existed  for  a  long  time,  granulation-tissue 
is  formed,  which  usually  absorbs  portions  of  the  root  and  the 
alveolus.  A.  Witzel  holds  the  opinion  that  the  granulations 
principally  spring  from  the  medulla  of -.the  alveolus.  Such 
new  formations  may  be  seen  around  the  cervical  as  well  as  the 
apical  portion  of  the  root,  and  always  induce  a  rapid  loosening 
of  the  tooth. 

Subjective  Phenomena. — Pyorrhoea  alveolaris  in  its  beginning 
usually  is  not  noticed  by  the  patient,  and  even  in  its  later  stages 
causes  no  ]5ain.  The  patient  complains,  however,  of  an  uneasy, 
annoying  sensation  in  the  teeth  and  jaws.  There  may  be  loss  of 
appetite,  although  this  can  be  attributed  to  constitutional  causes 
as  well  as  to  the  local  disease.  The  teeth  in  advanced  stages, 
even  though  quite  loose,  are  tolerably  comfortable  in  mastica- 
tion so  long  as  the  roots  have  not  been  absorbed  by  granula- 
tions. "When,  however,  this  happens,  the  tooth  becomes  sensi- 
tive to  pressure  and  percussion.  Such  a  tooth,  if  subjected  to 
mechanical  violence,  usually  reacts  by  a  painful  acute  attack  of 
purulent  diffuse  pericementitis.  Should  the  pulp  of  a  tooth 
become  devitalized  in  consequence  of  pyorrhoea  alveolaris,  the 
patient  has  no  pain  whatever  from  this  source. 

Differential  Diagnosis. — Pyorrhoea  alveolaris  might  be  .  con- 
founded with  a  deposition  of  salivary  calculi,  which  in  some  in- 
stances gives  rise  to  symptoms  similar  to  those  of  true  pyorrhoea 
alveolaris.  The  principal  characteristic  of  pyorrhoea  caused 
by  salivary  calculi  is  that  it  yields  to  local  treatment  in  a  com- 
paratively short  space  of  time,  and  usually  does  not  return  so  long 
as  the  necks  of  the  teeth  are  kept  free  from  calculary  deposits. 

Another  disease  which  might  be  mistaken  for  pyorrhoea  alveo- 
laris is  chronic  hyperplastic  diffuse  pericementitis,  which  some- 
times is  accompanied  by  a  purulent  inflammation.  As  the  latter 
disease  mostly  occurs  in  devitalized  teeth,  and  generally  is  con- 
fined to  one  tooth,  the  diagnosis  becomes  comparatively  easy. 

30 


450  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

A  process  in  many  respects  similar  to  the  one  under  consider- 
ation is  "  senile  atrophy  of  the  jaw-bones."  This,  as  a  matter  of 
course,  is  found  in  old  persons,  although  exceptionally  we  meet 
with  it  in  middle  age.  The  characteristic  feature  of  this  process 
is  a  gradual  wasting  of  the  alveolus,  and,  if  the  person  is  other- 
wise healthy,  no  pus  will  be  visible  around  the  necks  of  the 
teeth.  The  gums  are  generally  of  healthy  appearance,  although 
sometimes  they  may  be  slightly  inflamed.  In  the  early  stage 
of  senile  atrophy  of  the  jaws,  the  necks  of  the  front  teeth 
become  denuded  of  their  gums,  first  upon  the  labial  surface. 
In  the  molars,  especially  the  upper  ones,  the  lingual  surfaces  are 
affected  first,  and  we  often  see  the  lingual  roots  of  these  teeth 
entirely  bare.  The  same  atrophy  is  noticed  after  the  extraction 
of  the  molars  on  one  side  of  the  jaw.  The  teeth  in  the  oppo- 
site jaw  having  lost  their  normal  antagonism,  on  account  of  the 
absorption  of  the  alveolus,  apparently  elongate,  and  subse- 
quently fall  out.  This  process  in  a  healthy  person  usually  makes 
but  little  progress,  especially  when  all  or  most  of  the  teeth  are 
present  in  the  dental  arch.  When,  on  the  contrary,  the  system 
is  attacked  by  a  chronic,  wasting  disease,  we  soon  notice  chronic 
purulent  pericementitis,  more  or  less  pronounced,  around  the 
loose  teeth.  Almost  the  only  characteristic  of  senile  atrophy  in 
this  form  is  that  the  calculary  deposits  seldom  are  seen  beneath 
the  alveolar  border.  In  such  a  complication,  senile  atrophy  of 
the  jaws  exhibits  the  picture  of  pyorrhoea  alveolaris,  and  yet 
senile  atrophy  combined  with  pericementitis,  even  though  the 
system  be  impaired,  yields  to  proper  treatment.  Such  teetb,  as 
a  matter  of  course,  are  loose  and  will  remain  so,  but  they  may 
be  serviceable  and  be  preserved  for  many  years. 

The  prognosis  of  pyorrhoea  alveolaris  depending  upon  constitu- 
tional derangements  is  not  altogether  hopeless,  provided  the 
general  disturbance  can  be  combated,  although,  in  most 
instances,  when  the  calculary  deposits  have  extended  beyond 
the  middle  portion  of  the  root,  the  saving  of  the  tooth  becomes 
doubtful.  In  such  a  case  the  prognosis  is  the  worse  the  older 
the  patient;  while  the  disease,  if  occurring  under  thirty  years 
of  age,  is  mostly  curable.  When  the  disease  has  lasted  for 
some  time,  granulation-tissue  often  arises,  which,  if  situated 
around  the  neck  of  the  tooth,  and  accessible  to  treatment,  may 
not  prevent  the  tooth  from  being  saved.  Should,  on  the  con- 
trary, granulomata  develop  at  the  apex  of  the  root,  the  prognosis 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  451 

of  tile  tooth  becomes  doubtful.  Although  we  must  admit  that 
pyorrhoea  alveolaris  is  a  disease  not  always  amenable  to  treat- 
ment, we  ought  not  to  sacrifice  the  teeth  unless  they  cause 
trouble.  The  author  not  infrequently  has  seen  teeth  so  loose 
that  they  might  have  been  removed  by  the  fingers,  the  calculary 
deposits  besides  being  present  more  than  half-way  toward  the 
apex  of  the  root,  and  yet  they  have,  under  proper  treatment, 
grown  firmer  in  their  sockets. 

X.  Chronic  Purulent  Circumscribed  Pericementitis,  so-called 
"Blind  Abscess. "^-This  form  of  pericementitis  is  mostly  the 
outcome  of  repeated  attacks  of  an  acute  non-purulent  circum- 
scribed pericementitis,  more  especially  wdien  due  to  constitu- 
tional derangements.  It  is  also  known  to  arise  from  foreign 
bodies,  such  as  bristles  of  a  tooth-brush,  fine  fish-bones,  etc., 
wlien  obtaining  access  into  the  pericementum.  In  a  healthy 
person  the  presence  of  a  foreign  body  in  the  pericementum 
usually  leads  to  an  acute  inflammation,  while  in  poorly-consti- 
tuted patients  such  an  irritation  may  lead  to  a  chronic  suppur- 
ative inflammation.  It  seems  that  the  staphylococci  intro- 
duced into  the  depth  of  a  tissue  cause  suppuration  easier  in 
the  latter  than  in  the  former  instance. 

Diagnosis. — Besides  chronic  purulent  circumscribed  perice- 
mentitis, there  is  often  present  chronic  hyperplastic  pulpitis, 
the  more  pronounced  the  longer  the  blind  abscess  has  existed. 
In  the  beginning  the  abscess  causes  but  little  discomfort  to  the 
patient,  except  that  occasionally  the  aflfected  tooth  is  sensitive 
to  thermal  changes.  From  time  to  time  the  patient  notices  a 
swelling  of  the  gum  corresponding  to  the  diseased  portion  of 
the  pericementum.  The  swelling  upon  the  evacuation  of  the 
pus  soon  disappears,  and  with  it  the  tooth  is  comfortable,  until 
another  subacute  attack  sets  in.  These  paroxysms  of  pain  last 
from  two  to  four  days,  while  the  intervals  between  the  attacks 
may  last  from  one  to  six  months.  The  disease  is  met  with 
both  in  sound  and  carious  teeth,  though  the  latter  process  in 
this  form  of  pericementitis  never  extends  to  the  pulp-chamber. 
The  color  of  the  aftected  teeth  always  is  normal,  and  trans- 
illumination wijl  yield  but  negative  results.  The  tooth  is 
somewhat  loose  ■  in  its  socket,  and  quite  painful  to  pressure, 
especially  in  the  direction  toward  the  inflamed  portion  of  the 
pericementum.  Cold  water  or  the  inhalation  of  cold  air  pro- 
duces excruciating  pains  lasting  from  ten  minutes  to  half  an 


452  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

hour.  Pressure  upon  the  gum  over  the  inflamed  pericemen- 
tum is  painful,  at  the  same  time  causing  the  oozing  forth  of  pus 
from  the  ahscess,  the  pus  making  its  appearance  between 
the  neck  of  the  tooth  and  the  surrounding  gum.  Percussion 
upon  the  affected  tooth  is  painful,  and  elicits  a  distinctly  dull 
sound,  especially  when  directed  toward  the  inflamed  portion 
of  the  pericementum. 

Subjective  Phenomena. — The  pain  in  chronic  purulent  circum- 
scribed pericementitis  is  principally  due  to  pulpitis.  In  all 
cases  that  have  come  under  ni}^  observation,  chronic  hyper- 
plastic 'pulpitis  was  present,  which  by  an  additional  irritation, 
such  as  an  accidental  hard  bite  or  extreme  thermal  change, 
assumed  an  acute  character.  The  pain  is  of  throbbing  char- 
acter and  excruciating.  Articulation  is  impossible,  because  the 
tooth  is  raised  in  its  socket.  Upon  attempting  to  open  the  pulp- 
chamber  we  find  the  dentine  abnormally  sensitive,  often  induc- 
ing a  paroxysm  of  almost  unbearable  pain.  Chronic  purulent 
circumscribed  pericementitis  sometimes  may  be  accompanied  by 
a  slight  rise  of  temperature,  which  usually  occurs  toward  evening. 

Differential  Diagnosis. — Chronic  purulent  circumscribed  peri- 
cementitis may  be  confounded  with  acute  purulent  difli"use  peri- 
cementitis. The  principal  characteristic  of  the  former  disease 
is  that  the  tooth  is  of  normal  color  and  contains  a  living  pulp, 
while  the  pulp  of  a  tooth  attacked  b}^  acute  purulent  diffuse 
pericementitis  is  always  devitalized  and  in  most  instances  dis- 
colored. 

The  prognosis  of  teeth  affected  by  chronic  purulent  circum- 
scribed pericementitis  as  such,  would  be  quite  favorable,  if  by 
some  means  we  were  able  to  extirpate  the  diseased  pulp. 
Aside  from  the  dentine  being  extremely  sensitive  to  the  action 
of  the  bur,  the  pericementitis  renders  the  tooth  painful  to 
pressure,  and  consequently  such  teeth  are  usually  lost. 

XI.  Chronic  Purulent  Apical  Pericementitis. — Under  this  head 
I  propose  to  describe  a  form  of  chronic  abscess  principally  con- 
fined to  the  apices  of  the  roots  of  the  teeth.  This  disease  is 
always  the  outcome  of  an  acute  or  sometimes  subacute  non- 
purulent apical  pericementitis,  mainly  depending  upon  the  con- 
stitutional peculiarities  of  the  patient.  The  better  the  constitu- 
tion, the  more  acute  and  severe  will  be  the  pericementitis;  on 
the  other  hand,  the  poorer  the  constitution,  the  less  acute  (sub- 
acute) and  the  more  chronic  the  inflammatory  process  will  be. 


PERICEMENTITIS    IX    ITS    CLINICAL    ASPECTS,  453 

Diagnosis. — A  tooth  afiected  with  chronic  purulent  apical 
pericementitis  is  somewhat  loose  in  its  socket,  although  the 
gum  around  the  neck  of  the  tooth  is  firmly  attached  and  appears 
comparatively  healthy.  This  disease  most  frequently  occurs  in 
teeth  the  pulps  of  which  have  been  largely  exposed  and  subse- 
C[uently  died  from  moist  gangrene  or  chronic  purulent  pulpitis. 
The  pus,  therefore,  has  had  an  opportunity  to  escape  from  the 
abscess  through  the  apical  foramen,  whereby  the  chronic  inflam- 
mation usually  remains  limited  to  the  apical  portion  of  the  root. 
The  teeth  usually  are  much  discolored.  The  oral  mucosa  in  the 
vicinity  of  the  apex  of  the  affected  root  may  be  slightly  swollen 
and  sensitive  to  pressure,  or  may  appear  normal.  Percussion 
and  pressure  upon  the  tooth  in  the  direction  of  the  apex  of  the 
afiected  root  always  is  more  or  less  painful,  and  the  former  will 
elicit  a  distinctly  dull  sound.  The  principal  characteristic  of 
such  teeth  is  that  as  soon  as  the  opening  of  the  pulp-canal  be- 
comes temporarily  obstructed  by  particles  of  food  or  a  piece  of 
cotton,  severe  pain  is  the  result.  When  a  tooth  attacked  by 
chronic  purulent  apical  pericementitis  is  extracted,  we  some- 
times find  attached  to  the  apex  of  the  root  the  abscess  inclosed 
in  a  more  or  less  spherical  bag.  In  other  instances  the  sac  is 
torn  in  the  extraction  of  the  tooth. 

"  Subjective  Plienoraeiia. — As  long  as  the  pulp-canal  remains  open 
and  the  pus  is  able  to  escape  freely,  chronic  purulent  apical 
pericementitis  produces  but  little  pain,  though  the  tooth  may  be 
tender  in  mastication.  Thermal  changes  applied  to  such  teeth 
have  no  effect. 

Differential  Diagnosis. — The  only  disease  with  which  chronic 
purulent  apical  pericementitis  might  be  confounded  is  chronic 
purulent  diffuse  pericementitis.  In  the  latter  disease,  however, 
pus  usually  is  eliminated  when  pressure  is  applied  upon  the  gum 
in  the  vicinity  of  the  affected  root.  Besides,  the  gum  in  the 
latter  disease  never  is  attached  to  the  neck  of  the  tooth,  and 
the  obstruction  of  the  pulp-canal  by  food  or  cotton  usually  will 
produce  no  trouble,  whereas  in  cases  of  chronic  purulent  apical 
pericementitis  such  an  obstruction  is  followed  by  severe  pain. 

The  prognosis  of  teeth  affected  with  chronic  purulent  apical 
pericementitis  much  depends  upon  the  constitution  of  the 
patient  and  upon  his  toleration  to  pain.  Another  fact  has  to 
be  taken  into  consideration, — viz,  the  condition  of  the  apex 
of  the  root  of  the  affected  tooth.     When  the  disease  has  existed 


454  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

for  some  time,  granulation-tissue  will  arise,  partially  absorbing 
the  root,  whereby  usually  the  tooth  becomes  lost.  The  prog- 
nosis of  chronic  purulent  apical  pericementitis  may  be  expressed 
in  short  as  follows :  If  the  disease  has  not  lasted  long  enough 
to  affect  the  apex  of  the  root,  and  we  are  able  to  destroy  the  so- 
called  pyogenic  membrane  and  afterward  thoroughly  disinfect 
and  fill  the  pulp-canal,  such  a  tooth  may  be  saved.  If,  on  the 
contrary,  the  end  of  the  root  has  been  absorbed  by  granula- 
tions, or  the  patient  will  not  submit  to  the  destruction  of  the 
pyogenic  membrane,  the  tooth  should  preferably  be  extracted. 

XII.  Chronic  Purulent  Diffuse  Pericementitis. — In  most  in- 
stances the  disease  under  consideration  originates  from  acute 
non-purulent  diffuse  pericementitis,  or  chronic  purulent  pulpitis. 
It  may  also  develop  after  the  death  of  the  pulp  by  gangrene. 

Diar/nosis. — A  tooth  affected  with  purulent  diffuse  perice- 
mentitis is  quite  loose  in  its  socket,  and  can  be  moved  laterally 
as  well  as  perpendicularly  without  causing  much  pain.  Articu- 
lation, on  the  contrary,  is  always  painful.  The  tooth  usually  is 
discolored,  indicative  of  the  devitalization  of  its  pulp.  The 
mucous  membrane  around  the  root  of  the  affected  tooth  is  more 
or  less  inflamed,  tumefied,  and  soft  to  the  touch.  The  color  of 
the  gum  is  dark  red,  often  exhibiting  a  bluish  ring  around  the 
neck  of  the  tooth.  The  gum  has  lost  its  attachment  to  the 
neck,  and  often  we  are  able  to  pass  a  fine  probe  between  the 
tooth  and  the  gum,  even  for  some  distance  into  the  perice- 
mentum, without  producing  either  hemorrhage  or  pain. 

Pressure  upon  the  gum  with  the  point  of  the  index  finger  is 
somewhat  painful,  and  will  always  be  followed  by  an  evacuation 
of  more  or  less  pus.  In  advanced  stages  the  affected  tooth 
sometimes  becomes  extremely  sensitive  to  pressure  in  one  or 
more  directions.  This  indicates  that  an  absorption  of  the  root, 
or  a  new  formation  of  bone-tissue,  either  in  the  hyperplastic 
pericementum  or  upon  the  walls  of  the  socket,  is  present.  Per- 
cussion upon  the  crown  of  a  tooth  affected  bj'  chronic  purulent 
diffuse  pericementitis  always  is  painful,  and  elicits  the  dullest  of 
all  sounds  produced  by  percussion  of  teeth  in  the  mouth.- 

Subjective  Phenomena. — With  the  exception  of  pain  in  mastica- 
tion, the  patient  experiences  but  little  discomfort  from  a  tooth 
attacked  by  chronic  purulent  diffuse  pericementitis. 

Differential  Diaynosis. — The  disease  under  consideration  may 
be  confounded  with  chronic  hyperplastic  diftuse,  with  chronic 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  455 

purulent  apical  pericementitis,  witli  alveolar  abscess,  and  with 
necrosis  of  the  jaw-bones. 

Chronic  hyperplastic  diffuse  pericementitis  can  hardly  be  dif- 
ferentiated from  chronic  purulent  diffuse  pericementitis,  espe- 
cially since,  in  advanced  stages,  the  former  disease  always  is 
associated  with  the  latter. 

Chronic  purulent  apical  pericementitis  is  characterized  by  the 
gum  being  closely  attached  to  the  neck  of  the  affected  tooth ; 
while  in  chronic  purulent  diffuse  pericementitis  the  gum  always 
is  found  detached,  emitting  pus  upon  pressure.  Alveolar  abscess 
may  be  differentiated  from  chronic  purulent  diffuse  perice- 
mentitis by  the  oedema  of  the  face,  which,  in  the  majority  of 
cases,  is  present  in  the  former  disease.  Another  characteristic 
of  alveolar  abscess  is  the  fistula  in  the  mucous  membrane,  com- 
municating with  the  abscess,  which  never  is  found  in  chronic 
purulent  diffuse  pericementitis. 

I^ecrosis  of  the  jaw-bone  is  recognized  by  the  denuded  sur- 
face of  the  bone  presenting  a  roughness  when  a  probe  is  passed 
over  it.  Here  we  always  find  the  periosteum  more  or  less 
detached  from  the  surface  of  the  bone.  In  cases  where  the 
necrosis  originated  from  chronic  purulent  pericementitis,  it 
usually  is  limited  to  the  surrounding  alveolus  of  one  tooth. 
"When,  on  the  contrary,  the  necrosis  is  of  syphilitic  or  phosphoric 
origin,  it  may  involve  many  teeth  simultaneous!}-,  although  in 
such  an  instance  the  teeth  may  still  be  alive. 

The  jjrognosis  of  teeth  affected  with  chronic  purulent  diff'use 
pericementitis  mainly  depends  upon  the  constitution  of  the 
patient  and  the  stage  to  which  the  disease  has  advanced.  As 
long  as  it  is  not  associated  with  diffuse  hyperplastic  perice- 
mentitis, and  the  constitution  of  the  patient  is  not  impaired,  the 
prognosis  is  fair.  The  presence  of  hyperplastic  new  formations 
in  the  pericementum  is  indicated  by  pains  when  even  slight 
pressure  is  brought  to  bear  upon  the  tooth.  In  such  cases  it 
ought  to  be  removed.  On  the  other  hand,  when  granulations 
are  absent  and  the  pulp-canal  is  carefully  disinfected,  and,  after 
the  cessation  of  the  formation  of  pus,  is  thoroughly  filled,  such 
a  tooth  might  be  saved. 

XIII.  Chronic  Alveolar  Abscess. — Under  the  foregoing  heads 
I  have  described  the  morbid  changes  in  the  pericementum 
alone ;  in  the  following  I  propose  to  dwell  upon  the  secondary 
processes  subsequent  to  pericementitis. 


456  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

When  purulent  pericementitis  has  lasted  for  some  time,  the 
inflammation  spreads  to  the  neighboring  bone-tissue,  which 
process,  though  secondary  to  pericementitis,  must  be  regarded 
as  a  disease  of  the  jaw-bones.  Among  the  forms  of  inflamma- 
tion of  the  root-membrane  principally  causing  chronic  alveolar 
abscess,  I  would  mention  chronic  purulent  difl:"ase  and  chronic 
hyperplastic  pericementitis. 

Diagnosis. ^-In  the  early  stage  of  a  chronic  alveolar  abscess  the 
mucous  membrane  over  the  affected  root  is  considerably  swollen 
and  softened,  similar  in  appearance  to  that  found  in  chronic 
purulent  diflfuse  pericementitis.  In  later  stages,  almost  invari- 
ably a  fistulous  communication  with  the  abscess  is  present,  due 
to  an  ulcerative  destruction  of  the  mucosa.  In  quite  chronic 
cases  the  fistula  becomes  closed  from  time  to  time,  thus  pro- 
ducing the  formation  of  a  parulis  (so-called  "  gum-boil").  .  This 
formation  is  characteristic  of  chronic  alveolar  abscess  when  the 
periosteum  is  neither  much  thickened  nor  detached  from  the 
bone.  Should  the  pericementum  be  hypertrophied  or  detached, 
no  gum-boil  is  found,  the  opening  of  the  fistula  is  not  obstructed, 
and  the  disease  has  advanced  to  a  further  stage, — <>.,  periostitis, 
or  necrosis  of  the  jaw-bone.  In  slowly-progressing  cases  we 
sometimes  see  around  the  parulis  a  growth  of  granulation-tissue^ 
in  shape  and  size  of  a  pea.  In  rare  instances,  especially  in  the 
teeth  of  the  upper  jaw,  the  fistula  does  not  break  open  through 
the  mucous  membrane,  but  the  pus  is  evacuated  around  the 
neck  of  the  afiected  tooth.  Exceptionally  the  fistulous  opening 
is  not  seen  in  the  vicinity  of  the  aifected  root,  but  some  distance 
from  it,  in  which  instance  it  may  be  ditficult  to  find  the  tooth. 
It  occurs,  though  rarely,  that  the  fistula  of  one  of  the  upper 
front  teeth  opens  at  the  border  of  the  hard  palate.  The  fact 
that  the  disease  under  consideration  always  is  caused  by  a  devi- 
talized tooth  will  assist  us  in  clearing  the  diagnosis.  Further- 
more, pressure  and  percussion  upon  the  afifected  tooth  are 
always  sensitive,  though  such  a  tooth  may  not  be  elongated  or 
loose  in  its  socket.  In  quite  chronic  cases,  where  the  granulations 
have  absorbed  portions  of  the  root  and  the  alveolus,  the  tooth 
is  markedly  sensitive  to  pressure  and  percussion.  In  such 
cases  we  not  infrequently  find  the  alveolar  process  of  both 
neighboring  teeth  lost,  which  loss  often  can  be  distinctly  detected 
by  the  point  of  thei  ndex  finger. 

Subjective  Phenomena. — Chronic  alveolar  abscess,  in  its  incipi- 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  -457 

ent  stage,  wheu  osteitis  sets  in,  is  accompanied  by  drawing  paius, 
and  sometimes  by  fever.  Daring  this  period,  which  usually 
lasts  from  one  to  three  days,  the  tooth  is  sensitive  to  the  touch 
and  to  mastication.  In  time  the  process  assumes  a  less  acute 
course,  and  when  the  gum-boil  becomes  established,  the  patient 
suffers  no  more  pain.  Only  the  rupturing  of  the  parulis,  from 
time  to  time,  indicates  the  existence  of  a  chronic  alveolar 
abscess. 

Differential  Diagnosis. — In  most  instances  a  chronic  alveolar 
abscess  is  easily  recognized.  Where  no  fistulous  opening  is 
present,  it  might,  however,  be  confounded  with  chronic  puru- 
lent cliff'use  or  circumscribed  pericementitis,  as  well  as  chronic 
purulent  hyperplastic  pericementitis.  Hyperplastic  and  diffuse 
pericementitis  are  so  similar  to  a  chronic  alveolar  abscess  with- 
out a  fistula,  that  a  correct  differentiation  is  not  always  possible. 
Chronic  purulent  circumscribed  pericementitis,  however,  is  char- 
acterized by  the  living  pulp  the  tooth  mostly  contains,  while 
chronic  alveolar  abscess  occurs  only  in  devitalized  teeth. 

The  2^rognosis  of  teeth  affected  with  chronic  alveolar  abscess, 
on  an  average,  is  good,  especially  in  cases  which  have  not  existed 
long  enough  to  develop  granulations  at  the  end  of  the  root. 
The  rule  here,  as  in  the  treatment  of  teeth  affected  with  chronic 
purulent  pericementitis,  is  that  so  long  as  the  root  has  not  been 
absorbed  the  tooth  can  be  saved.  The  success  of  the  treatment, 
however,  depends  upon  the  ability  of  the  operator  and  the  form 
and  accessibility  of  the  pulp-canal  of  the  affected  tooth.  If  the 
pulp-canal  can  be  thoroughly  disinfected  and  filled,  and  no  fill- 
ing-material has  been  pushed  through  the  apical  foramen  of  the 
ro'ot,  the  tooth  is  usually  saved. 

XIV.  Cementitis  and  Eburnitis.  Inflammation  of  the  Cemen- 
tum  and  Dentine. — As  already  mentioned,  wherever  a  chronic 
inflammatory  process  has  existed  for  some  time,  granulation- 
tissue  develops,  leading  to  a  gradual  destruction  of  the  root  of 
the  tooth,  by  cementitis  and  eburnitis.  These  processes,  under 
the  microscope,  are  characterized  by  bay-like  excavations  in  the 
hard  tissues,  often  filled  ^^-ith  multinuclear  protoplasmic  bodies. 
In  some  instances  even  new  formations  of  bone  are  met  with 
in  the  adjacent  tissues. 

Diagnosis. — To  the  naked  eye  the  roots  of  teeth  affected  by 
cementitis  and  eburnitis  present  deep  and  irregular  cup-shaped 
excavations,  between  which  sharp  projections  are  left.     When 


458  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

pressure  is  exerted  upon  the  crown  of  a  tooth  affected  by 
cementitis  and  eburnitis,  the  sharp  projections  irritate  the  adja- 
cent pericementum,  thus  causing  more  or  less  pain.  The  gum 
in  the  vicinity  of  the  affected  root  is  in  some  instances  inflamed, 
in  others  normal,  depending  upon  the  condition  of  the  perice- 
mentum. 

The  only  subjective  jjhenomenon  of  cementitis  and  eburnitis  is 
indeed,  as  mentioned  before,  that  pain  is  produced  on  pressure 
upon  the  tooth. 

Differential  Diagnosis. — A  diagnosis  of  this  disease  cannot  be 
"made  with  any  degree  of  certainty  until  the  tooth  has  been 
extracted. 

The  'prognosis  of  teeth  affected  with  cementitis  and  eburnitis 
always  is  unfavorable,  since  the  sharp  projections  of  the  denuded 
root  continually  keep  irritating  the  pericementum.  Such  teeth 
are  usually  lost. 

XV.  Periostitis,  Osteitis,  and  Osteomyelitis.— As  these  dis- 
eases usually  are  associated  with,  and  the  outcome  of,  puru- 
lent pericementitis,  I  shall  consider  them  under  one  head. 
Occasionally  they  occur  in  consequence  of  mechanical  ^dolence, 
— z.e.,  by  a  hard  blow;  in  difficult  eruption  of  the  wisdom-teeth, 
especially  the  lower  ones ;  or  in  tearing  of  the  gum  in  extract- 
ing badly-decayed  roots.  These  diseases  alwaj^s  arise  by  an 
infection,  sometimes  accomplished  b}'  the  use  of  septic  instru- 
ments or  unclean  tooth-picks,  pushed  under  the  gum. 
"  Diagnosis. — The  inflammatory  process  attacking  the  perios- 
teum extends  over  the  bone,  either  in  the  form  of  osteitis,  osteo- 
myelitis, or  necrosis.  Periostitis  in  the  beginning  always  is 
acute,  and  causes  swelling  of  the  mucous  membrane,  and  some- 
times considerable  oedema  of  the  lip  and  cheek.  When  this 
occurs  in  the  lower  jaw,  the  swelling  soon  involves  the  sub- 
maxillary gland,  and  often  spreads  down  to  the  shoulder.  To- 
gether with  the  periostitis,  usually  there  is  a  swelling  and  rigid- 
ity of  the  muscles  of  mastication,  whereby  the  patient  is  unable 
to  open  the  mouth.  Periostitis,  when  a  sequel  of  pericementitis, 
mostly  is  preceded  by  osteitis  .and  osteomyelitis,  in  which  case 
the  inflammation  first  attacks  the  bony  socket,  before  its  peri- 
osteal covering  becomes  involved.  In  cases  of  traumatic  origin, 
however,  as  a  rule,  the  periostitis  is  the  primary  process,  while 
the  osteitis,  osteomj^elitis,  or  necrosis  are  secondarj^  occurrences. 
Periostitis  in  an  acute  stage  may  exist  alone ;  but  subacute  or 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  459 

■chronic  cases  are  always  accompanied  by  more  or  less  osteitis, 
osteomyelitis,  or  necrosis  of  the  jaw-bones.  In  the  majority  of 
instances  an  inflammation  of  the  alveolar  periosteum  is  the 
result  of  a  clentalized  tooth,  which  may  be  easily  recognized 
by  its  dark  color.  The  extent  of  the  area  of  the  affected  alveolus 
greatly  varies.  In  some  cases  it  is  only  as  large  as  a  pin's 
head,  while  in  others  the  process  may  involve  the  alveolar  pro- 
cesses of  four  or  five  teeth  in  a  comparatively  short  space  of 
time.  When  purulent  periostitis,  osteitis,  or  osteomyelitis  are 
present,  as  a  rule,  one  or  several  fistulous  openings  are  seen  in 
the  gums.  Sometimes,  however,  the  pus  is  evacuated  along  the 
necks  of  the  teeth.  In  quite  severe  and  chronic  cases,  espe- 
cially those  of  the  lower  jaw,  the  pus,  after  perforating  the  bone, 
makes  its  appearance  on  the  outer  surface  of  the  skin.  When 
the  diseases  under  consideration  originate  in  consequence  of 
difficult  eruption  of  the  lower  wisdom-teeth,  the  swelling  and 
the  formation  of  pus  may  be  copious,  especially  in  acute  cases, 
while  those  of  a  more  chronic  tj^De  seldom  exhibit  much  swell- 
ing or  pus.  The  gum  over  the  affected  periosteum  usually  is 
spongy  to  the  touch,  and,  according  to  the  stage  the  inflamma- 
tory process  has  advanced,  is  characterized  by  more  or  less  red- 
ness and  heat.  Not  infrequently  periostitis,  osteitis,  and  osteo- 
myelitis, when  present  in  the  upper  jaw,  extend  into  the  antrum, 
or  even  the  nasal  cavities,  on  which  emergencies  I  shall  dwell 
more  fully  in  a  separate  chapter.  When  chronic  pericementitis 
becomes  diffuse,  it  may  be  accompanied  by  the  formation  of 
fistulse  and  abscesses  in  the  neighboring  tissues.  The  writer 
has  seen  patients  who,  in  consequence  of  a  neglected  chronic 
alveolar  abscess,  suffered  from  secondary  abscesses  in  several 
places  of  the  neck,  near  the  clavicle.  There  are  even  fatal  cases 
on  record  in  which  the  pus  found  its  way  into  the  mediastinum, 
producing  secondary  abscesses,  purulent  pleuritis,  or  oedema  of 
the  lungs. 

Suhjedive  Phenomena. — In  periostitis,  osteitis,  and  osteomye- 
litis, much  depends  upon  the  constitution  of  the  individual.  The 
better  the  general  health  of  the  patient,  the  more  acute  is,  as  a 
rule,  the  inflammatory  process,  and  the  greater  will  be  the  suf- 
fering, especially  in  diffuse  inflammation.  In  such  instances 
these  diseases  always  are  accompanied  by  more  or  less  fever  and 
other  derangements  of  the  system,  the  more  severe  the  greater 
the  number  of  deep-seated  abscesses  formed  in  the  neighbor- 


460  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

hood  of  the  inflamed  parts.  The  majority  of  cases  of  perios- 
titis, osteitis,  and  osteomyelitis,  however,  do  not  become  diffuse, 
but  remain  localized  to  a  comparatively  small  area.  Then, 
should  the  trouble  be  caused  by  pericementitis,  the  patient  ex- 
periences but  little  pain  from  the  periostitis,  while  osteitis  and 
osteomyelitis  are  accompanied  by  excruciating  pains.  As  soon, 
however,  as  the  alveolar  process  is  perforated  by  the  piis  the 
pain  subsides,  and  periostitis,  in  itself  not  very  painful,  as  stated 
before,  takes  issue. 

Differential  Diagnosis. — Periostitis  in  either  its  localized  or 
diffused  form  cannot  easily  be  mistaken  for  another  disease, 
while  osteitis  and  osteomyelitis  may  sometimes  be  confounded 
with  necrosis  of  the  jaw-bones,  the  more  so  since  it  mostly  is 
associated  with  the  former.  The  distinguishing  peculiarities  of 
necrosis  are  the  roughness  and  hardness  of  the  exposed  surface 
of  the  bone  to  the  probe.  The  periosteum  is  detached,  and  be- 
tween it  and  the  bone  a  considerable  amount  of  pus  is  continu- 
ally formed,  freely  escaping  upon  pressure.  Inflamed  bone  ap- 
pears softened  to  the  touch  of  the  probe;  its  surface,  when 
exposed,  looks  red,  its  periosteum  is  hypertrophied  and  more 
or  less  firmly  attached  to  the  diseased  bone. 

Prognosis. — Periostitis,  osteitis,  and  osteomyelitis,  occurring 
in  consequence  of  mechanical  violence,  usuall}^  yield  to  antisep- 
tic treatment  in  a  comparatively  short  space  of  time,  and  with- 
out the  loss  of  teeth.  When,  however,  these  diseases  are  due 
to  purulent  pericementitis,  the  loss  of  the  tooth,  together  with 
a  portion  of  the  alveolar  process,  cannot  be  avoided.  When 
secondary  abscesses  have  formed  in  the  region  of  the  neck  or 
the  mediastinum,  these  diseases  become  quite  serious,  as  a  rule,, 
and  sometimes  even  endanger  life. 

XVI.  "Lymphadenitis,"  Inflammation  of  the  Lymph- 
Ganglia. — The  name  "  lymphadenitis,"  though  generally  used, 
is  erroneous,  since  it  means  inflammation  of  a  lymph-gland, 
whereas  the  lymph-follicles  and  lymph-ganglia  are  not  glands, 
lacking  epithelial  structure  altogether.  Inflammation  of  the 
lymph-ganglia  is  most  common  in  the  submaxillary  region,, 
always  due  to  a  transmission  of  infectious  material  through  the 
lymph-vessels  into  the  lymph-ganglia.  There  are  persons  who, 
upon  the  slightest  non-purulent  inflammation  of  the  pulp  or 
the  pericementum,  react  with  a  swelling  of  the  submaxillary 
ganglia.      Purulent  pulpitis  and  pericementitis,  with  all  the 


PERICEMENTITIS    IN    ITS    CLINICAL    ASPECTS.  461 

inflammatory  complications  dependent  upon  them,  are  invari- 
ably accompanied  by  a  swelling  and  hardening  of  the  l^'mph- 
ganglia.  Gangrene  of  the  pulp  is  prone  to  cause  this  trouble. 
All  this  holds  s'ood  only  for  infectious  diseases  of  the  teeth  of 
the  lower  jaw,  while  those  of  the  upper  jaw  but  rarely  affect 
the  lymph-ganglia  in  the  submaxillary  region.  It  seems  that 
this  disease  is  more  common  in  youths  under  ten  years  than  in 
persons  more  advanced  in  age.  In  adults  it  frequently  occurs 
during  difficult  eruptions  of  the  wisdom-teeth,  or  after  their  ex- 
traction. In  some  instances  lymphadenitis  makes  its  appear- 
ance after  an  attempted  extraction  of  a  tooth  or  a  root,  in  which 
case,  however,  the  symptoms  never  are  severe. 

Diagnosis. — In  the  beginning  of  the  process  the  submaxillary 
ganglia  SAvell  and  become  hard.  The  covering  skin  is  rendered 
tense  and  hot,  and  the  enlarged  knot  immovable.  The  slight- 
est pressure  upon  it  is  painful.  The  SAvelling  in  mild  cases 
attains  the  size  of  a  Avalnut,  while  in  severer  ones  it  may  reach 
the  size  of  a  man's  fist  or  more.  There  is  great  rigidity  of  the 
muscles  of  the  jaw,  so  much  so  that  the  mouth  can  only  be 
opened  by  means  of  instruments.  The  principal  characteristic 
of  this  disease  is  that  there  usually  are  no  fistulous  openings 
present  in  the  gum.  Although,  as  a  rule,  the  inflammatory 
infiltration  soon  abates,  in  rare  instances  the  ganglia  suppurate, 
indicated  by  a  red  spot  upon  the  skin  covering  the  ganglia, 
and  by  the  fluctuation.  These  symptoms  usually  are  accom- 
panied by  more  or  less  fever. 

Subjective  Phenomena. — In  the  beginning  of  the  process  the 
patient  experiences  but  little  pain,  unless  something  comes  in 
contact  with  the  swollen  ganglia.  In  the  milder  forms  this  dis- 
ease does  not  cause  pain,  but  only  discomfort ;  while  the  severer 
cases,  accompanied  by  fever  and  the  formation  of  an  abscess, 
are  c[uite  distressing.  Eeal  pain  commences  as  soon  as  the 
submaxillary  ganglia  verge  to  suppuration. 

Differential  Diagnosis. — Taking  into  consideration  the  sub- 
jective symptoms,  and  Avhat  has  been  stated  concerning  the 
diagnosis  of  the  disease  in  question,  it  cannot  easily  be  mis- 
taken for  another  disease. 

Prognosis. — In  lymphadenitis  much  depends  upon  the  con- 
stitution of  the  patient.  Otherwise  healthy  persons,  when  at- 
tacked by  the  disease,  seldom  suflfer  much,  nor  are  the  ganglia 
apt  to  suppurate  except  in  a  so-called  lymphatic  constitution. 


462  THE    ANATOMY    AI^D    PATHOLOGY    OF    THE    TEETH. 

Some  very  acute  cases  may  become  annoying,  more  by  the 
protracted  swelling-  of  the  neck  and  the  disfigurement,  often 
lasting  for  weeks,  than  others  in  which  suppuration  has  taken 
place. 


CHAPTER  XXXIX. 

MORBID  ANATOMY  OF  PERICEMENTITIS. 

According  to  the  severit}^  of  the  irritation,  and  the  constitu- 
tional peculiarities  of  the  individual,  pericementitis  presents 
itself  as  acute  or  chronic,  either  of  which  may  be  non-purulent 
or  purulent.  Acute  pericementitis  is  not  infrequently  confined 
to  the  region  of  the  neck  of  the  tooth.  As  in  any  other  acute 
inflammatory  process,  it  may  issue  in  a  hemorrhage,  especially 
in  so-called  hsematophiles  or  bleeders,  who  upon  the  slightest 
injury  bleed  profusely,  both  from  open  wounds  at  the  surface  of 
the  body  and  from  a  comparatively  slight  inflammatory  process, 
such  as  ulitis  or  marginal  pericementitis.  In  my  collection  of 
microscopical  specimens,  which  embraces  thousands  of  objects 
from  pathological  teeth,  are  several  obtained  from  the  neck  of 
a  tooth  in  which  I  observed  tbe  presence  of  a  large  number 
of  clusters  of  hsematoidin  crystals  in  the  neck  layer  of  the  ce- 
mentum  as  well  as  in  the  subjacent  so-called  granular  layer  of  the 
dentine.  (See  Fig.  230.)  This  condition  may  be  termed  apoplexy 
or  hcemorrhagic  infaretus  of  the  hard  tissues  of  the  teeth.  In  my 
judgment,  it  is  impossible  to  explain  the  presence  of  hfematoidin 
in  the  cementum  and  the  dentine  without  a  previous  sufi'usal  of 
these  tissues  with  blood.  The  fact  that  the  cementum  of  the 
neck  is  rich  in  protoplasmic  bodies  and  the  granular  layer  of  the 
subjacent  dentine  rich  in  living  matter,  arranged  in  the  shape  of 
a  coarse  reticulum,  affords  an  explanation  of  this  remarkable 
condition. 

Acute  Non-Purulent  Pericementitis,  in  its  mildest  degree, 
with  lower  powers  of  the  microscope,  is  recognizable  by  the 
presence  of  nests,  filled  with  medullary  elements,  in  the  midst 
of  the  connective-tissue  bundles.  The  shape  of  these  nests  is, 
as  a  rule,  oblong,  corresponding  to  the  longitudinal  direction  of 
the  connective-tissue  bundles,  or  roundish,  in  accordance  with 
the   cross-section   of   bundles.     The    scantier   these    nests,  the 


MORBID    AXATOMY    OF    PERICEMENTITIS. 


463 


milder  is  the  inflammatory  process.  With  high  magnifying 
powers  of  the  microscope  we  learn  that  the  earliest  stage  of  the 
inflammation  consists  in  a  transformation  of  the  connective-tissue 
flbers  into  protoplasm.  With  the  knowledge  of  the  normal 
structure  of  the  pericementum  we  are  enabled  to  comprehend 
that  a  mere  liquefaction  of  the  basis-substance  is  sufficient  for 
the  reproduction  of  the  protoplasmic  condition  of  the  basis-sub- 
stance.    Such  a  reproduction  occurs  in  the  shape  of  streaks  in 


Fig.  230. 


^MMfifMi& 


Clusters  of  IIj:\rATOiDix  ix  the  Cemext  axd  Dextixe  of  the  Neck. 

T,  decalcified  tartar ;   C,  cementum  of  neck  with  numerous  clusters  of  heematoidin ;  J), 
granular  dentine  of  neck  ;   ff,  clusters  of  h£ematoidin  in  dentine.    Magnified  500  diameters. 


the  midst  of  a  bundle,  independently  of  the  original  protoplasmic 
bodies, — the  formerly  so-called  connective-tissue  cells.  (See 
Fig.  231.) 

According  to  the  spindle  shape  of  the  elementary  fields  of  the 
basis-substance,  spindle-shaped  protoplasmic  bodies  have  ap- 
peared, wholly  identical  with  the  normal  protoplasmic  bodies 
within  the  fibrous  connective  tissue.  All  these  bodies  are 
separated  from  one  another  by  light  rims,  and  connected  with 
each  other  by  the  delicate  threads  of  living  matter  traversing 


464 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


those  rims.  The  lineiy-granular  newly-appeared  protoplasmic 
bodies  soon  afterward  become  coarsely  granular,  which  means 
that  the  living  matter  therein  has  increased  in  bulk.  A  liquid 
exudation  as  such  is  never  visible  under  the  microscope,  but 
we  infer  its  presence  both  from  the  liquefaction  of  the  basis- 

FiG.  231. 


Acute  Peeicemextitis  of  a  Moderate   Degree. 

F,  fibers  of  pericementum  unchanged;  R,  B,  rows  of  inflammatory  or  embryonal  corpuscles; 
V,  capillary  blood-vessel  obliterated:  B,  bundles  of  pericementum  implanted  into  cementum; 
C,  C,  cement-oorpuscles  ;  *S',  basis-substance  of  cementum.    Magnified  .500  diameters. 

substance  and  the  increase  of  living  matter,  which  latter  can 
only  be  due  to  an  increased  afflux  of  nourishing  material.  These 
changes  take  place  in  the  newly-appeared  as  well  as  in  the 
original  protoplasmic  bodies,   the  nuclei   of  which  invariably 


MORBID    ANATOMY    OF    PERICEMENTITIS. 


465 


become  shining,  homogeneous,  and  enlarged,  owing  to  the  same 
cause  which  led  to  the  enlargement  of  the  points  of  intersection 
of  the  reticulum  of  living  matter. 

We  see  next  that  a  number  of  granules — the  points  of  inter- 
section of  the  reticulum — have  increased  in  size  to  such  an 
extent  that  they  resemble  small  nuclei,  and  from  these  foci  new 

Tig.  232. 


IxTExsE  Pericemkxtitis,  veegixg  ox  Suppuratiox  (Zoxe  2)  OF  Fig.  242. 

T,  T,  tracts  of  fibrous  connective  tissue  much  reduced  in  bulk;  iV,  A',  nests  of  inflammatory 
corpuscles  crowded  with  staphylococci :  S,  S.  clusters  of  staphylococci :  B.  R.  rows  of  inflam- 
matory corpuscles  in  broad  tracts  of  fibrous  connective  tissue.    Magnified  500  diame'ers. 

protoplasmic  elements  are  formed,  partly  shining  and  homo- 
geneous, partly  reticular  in  structure.  After  the  originally  solid 
lumps  of  living  matter  have  split  into  a  reticulum,  many  of  the 
newly-formed  elements  contain  solid  nuclei.  All  elements  are 
uninterruptedly  connected  with  each  other  by  delicate  threads 

31 


466 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


of  living  matter.  Thus,  the  inflammatory  infiltration  is  estab- 
lished at  first  in  the  shape  of  scattered  nests,  the  centers  of 
which  correspond  to  the  capillary  blood-vessels.  In  later  stages 
almost  the  whole  amount  of  the  connective  tissue  is  transformed 
into  medullary  elements  to  such  a  degree  that  only  scanty 
bundles  of  the  original  connective  tissue  are  left.  (See  Fig. 
232.) 

The  changes  in  the  wall  of  the  capillary  blood-vessels  are  of 
considerable  interest.  Doubtless  the  largest  accumulation  of  the 
inflammatory  elements  takes  place  in  the  immediate  neigh- 
borhood of  the  blood-vessels,  for  in  the  midst  of  many  nests 
capillaries  can  be  traced.  We  readily  understand  that  in  the 
immediate  vicinity  of  the  source  of  nutrition  the  inflammatory 
process  must  be  the  liveliest.     This  fact  has  been  taken  up  as  an 

Fig.  233. 


Inflamed  Peeicemextum  ix   ax  Early  Stage. 

J.,  capillary  blood-vessel,  the  endothelia  of  which  are  coarsely  granular  and  proliferatiDg : 
B,  medullary  or  inflammatory  elements,  imbedded  in  a  finely-gi-anular  basis-substance  :  C,  C, 
spindle-shaped  elements.    Magnified  lOUO  diameters. 

argument  by  those  who  assert  that  the  inflammatory  nests  are 
altogether  due  to  an  emigration  of  colorless  blood-corpuscles. 
I  am  strongly  opposed  to  this  opinion,  because  my  observations 
show  that  the  majority  of  the  inflammatory  elements  are  origi- 
nally connected  with  one  another  by  delicate  threads,  therefore 
representing  a  tissue.  The  endothelia  of  the  capillaries  share  in 
the  inflammation,  by  being  transformed  into  coarsely-granular, 
irregular  protoplasmic  bodies,  which,  by  division,  also  produce 
new  medullary  elements,  partly  nucleated,  partly  devoid  of 
nuclei.  By  the  new  formation  of  inflammatory  elements  from 
the  endothelia,  the  capillary  is  first  considerably  narrowed  in 
caliber,  and  afterward  completely  obliterated.     (See  Jig.  233.) 


MORBID    ANATOMY    OF    PERICEMEXTITIS.  467 

An  exuberant  growth  of  the  endothelia  will,  as  a  rule,  result  in 
the  destruction  of  the  capillaries  by  suppuration,  and  will  prob- 
ably give  rise  to  formations  which  I  shall  presently  describe. 

In  most  of  my  specimens  of  inflamed  pericementum  I  have 
met  with  a  singular  formation,  A  number  of  medullary 
elements  coalesce  into  globular  masses,  greatly  varying  in  size, 
and  in  some  instances  surrounding  a  central  polyhedral  space, 
evidently  made  by  the  compression  of  the  former  blood-vessel. 
The  globular  masses  are  either  composed  of  medullary  elements, 
shining,  homogeneous,  and  split  into  smaller  lumps  of  living 
matter,  or  they  are  continuous  masses  of  a  coarsely-granular 
protoplasm  in  which  varying  numbers  of  nuclei  are  seen.  There 
is  scarcely  any  doubt  that  the  latter  formations  have  arisen  from 
the  former  ones  through  confluence  of  the  single  medullary 
elements.  On  the  boundary  very  often  concentric  layers  of 
round  or  spindle-shaped,  finely-granular  elements  are  present. 
In  specimens  stained  with  a  solution  of  chloride  of  gold  the 
concentric  layers  are  of  a  pale  violet,  while  the  protoplasmic 
masses  inclosed  therein  exhibit  a  dark-purple  color.  Formations 
of  this  kind  are  well  known  in  inflamed  periosteum  and  medulla 
of  bone ;  they  have  been  termed  myeloplaxes,  myeloid  bodies, 
giant-cells,  etc.  All  the  well-known  hypotheses  as  to  their  sig- 
nificance disagree  with  what  I  have  seen, — viz,  the  formation  of 
territories  of  bone-tissue  from  these  clusters. 

My  specimens  show  plainly  that  in  the  so-called  plastic  inflam- 
mation of  the  pericementum  all  inflammatory  elements  remain 
connected  with  one  another,  and  thus  represent  a  medullary, 
embryonal,  or  indiflferent  tissue.  In  slight  degrees  of  inflamma- 
tion the  morbid  process  may  yield  to  what  has  been  termed 
"  the  resolution  of  inflammation."  ]!^othing  is  required  but  the 
re-formation  of  the  basis-substance,  and  the  normal  condition  is 
re-established,  sometimes  so  completely  that  no  trace  of  the 
former  inflammation  is  noticeable.  More  severe  forms  of  plastic 
pericementitis,  or  repeated  recurrences  of  the  inflammatory 
process,  will  result  in  a  new  formation  of  the  connective  tissue, 
the  so-called  hyperplasia.  Higher  degrees  of  plastic  pericemen- 
titis are  invariably  accompanied  by  inflammation  of  the  gum, 
the  cementum,  and  the  bony  alveolus. 

Cementitis  is  shown  under  the  microscope  by  the  presence  of 
bay-like  excavations  on  the  periphery  of  the  cementum,  and 
sometimes  also  beneath  the  surface.     These  excavations  are  filled 


468 


THE    AKATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


with  medullary  elements  or  multinu clear  protoplasmic  bodies. 
On  an  average,  the  excavations  are  deeper  and  more  numerous  in 
proportion  to  the  intensity  of  the  original  inflammatory  process. 
To  their  presence  is  due  the  peculiar  corroded  appearance  of 
the  cementum  in  teeth  extracted  during  an  attack  of  peri- 
cementitis.    (See  Fig.  234.) 

Fig.  234. 


Intense  Acute  Cementitis  and  Pericementitis. 

P,  perieementum  much  inflamed ;  P',  inflamed  pericementum  detached  from  cementum  ; 
2j,  dissolution  of  lime-salts  in  territories  along  the  border  of  cementum  ;  A,  A,  advanced  reduc- 
tion of  cementum;   E,  E,  enlarged  cement-corpuscles.     Magnified  500  diameters. 


Osteitis  of  the  bone  of  the  alveolus  is  manifested  in  its  incipi- 
ent form  by  a  dissolution  of  the  basis-substance  of  the  bony  tis- 
sue, in  the  shape  of  bay-like  excavations,  corresponding  to  the 
territories  of  the  bone-tissue.     "Within  the  decalcified  territories 


MORBID    ANATOMY    OF    PERICE3IEXTITIS. 


469 


coarsely-granular  bone-corpuscles  are  seen,  many  of  which  are 
distinctly  enlarged,  sending  forth  numerous  Lifurcating  off- 
shoots. The  territory  itself  is  reduced  to  its  protoplasmic  con- 
dition, indicated  by  a  fine  and  uniform  granulation.     In  many 


Fig.   285. 


IxciPiEXT  Osteitis  op  Alveolus.     Dissolution   of    Lime-Salts.     Eeappearaxce  of 

Territories. 

F,  still  calcified  framework  at  the  borders  of  the  territories :  C.  C,  enlarged  and  coarsely-gran- 
ular bone-corpuscles :  P,  P,  reappearance  of  protoplasm  within  the  territories  :  E,  cluster  of 
embryonal  or  inflammatory  corpuscles  ;  D.  divided  bone-corpuscle  :  B,  empty  bays,  the 
inflammatory  corpuscles  dragged  away ;  R,  large  empty  bay,  a  so-called  Howship's  lacuna. 
Magnified  500  diameters. 


places,  however,  clusters  of  coarse  granules  are  seen,  some  of 
which  have  considerably  increased  in  size,  approaching  that^of 
medullary  corpuscles,  the  ioflamed  bone  thus  appearing  to  be 
provided  with  far  more  bone-corpuscles  than  the  normal  bone. 


470 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


This  appearance  is  due  parti 3"  to  the  enlargement  of  the  old 
bone-corpuscles,  partly  to  their  splitting  up  into  two  or  more 
protoplasmic  bodies,  and  partly  to  the  formation  of  new  proto- 
plasmic bodies.  If  the  basis-substance  melts  completely,  the 
entire  existing  bone-tissue  is  rendered  protoplasmic,  and  by  a 

Fro.  236. 


Acute  Osteitis  ix  Alveolar  W^^ll. 

iV, 'iV,  normal  bone-corpuscles;  E,  territory  reduced  to  protoplasm:  /,  bone-corpuscles 
increased  in  size  and  number  ;  X,  Z,  enlarged  bone-corpuscles;  A',  ^,  medullary  spaces  much 
enlarged;  (7,  normal  medullary  canal  ;.  Jf,  muUinuclear  protoplasmic  body.  Magnified. 400 
diameters. 

new  formation  of  medullaiy  corpuscles  from  the  living  portion 
of  thejprotoplasm  medullary  or  inflammatory  corpuscles  arise 
filling  the'bay-like  excavations,  which  have  been  originated  by 
a  fusion^of  the   decalcified  territories.     Such  bay-like  excava- 


MORBID    ANATOMY    OF    PERICEMENTITIS.  471 

tions  appear  empty  when  specimens  made  from  dry  bone  are 
examined,  or  if,  in  cutting  the  section,  the  medullary  tissue  is 
dragged  away.  They  are  known  to  pathologists  as  Howship's 
lacuna.     (See  Fig.  235.) 

When  intense  acute  inflammation  begins  in  the  bony  socket 
of  the  alveolus,  the  image  under  the  microscope  is  somewhat 
diflerent,  No  regular  territorial  decalcification  takes  place,  but 
a  rapid  dissolution  of  the  lime-salts  in  circumscribed  nests 
occurs  independently  of  Haversian  canals.  The  previous  bone- 
corpuscles  and  the  living  matter  spread  throughout  the  basis- 
substance  of  the  bone  lead  to  the  rapid  appearance  of  inflam- 
matory or  medullary  corpuscles,  either  scattered  singly  in  a 
myxomatous  basis-substance  or  in  clusters  termed  myeloplaxes. 
In  the  center  of  such  an  inflammatory  nest,  as  a  rule,  a  newly- 
formed  capillary  blood-vessel  makes  its  appearance.  At  the 
periphery  of  the  inflamed  nest  decalcification  is  indicated  by 
more  or  less  crescentic  fields,  imperfectly  marked  as  to  territory, 
such  as  we  frequently  see  in  the  developing  bone-tissue  of 
embryos  between  the  third  and  sixth  months  of  intra-uterine  life. 
The  decalcification  invades  the  bone-tissue  difiiisely,  as  we  may 
infer  from  the  fact  that  we  see  many  enlarged  and  split-up  bone- 
corpuscles  without  the  reappearance  of  territories.  In  a  thor- 
oughly-calcified basis-substance  such  changes  of  the  bone-cor- 
puscles would  be  impossible.     (See  Fig.  236.) 

This  process  is  invariably  combined  with  osteomyelitis,  and 
the  result  of  both  processes  is  the  transformation  of  the  hard 
bony  tissue  into  a  soft  medullar}-  or  inflammatory  tissue.  In 
some  of  my  specimens  of  osteitis  this  change  is  exhibited  to  a 
very  high  degree,  so  that  only  small  islands  of  bony  tissue  are 
left  as  remnants  of  the  former  wall  of  the  alveolus. 

Chronic  Hyperplastic  Pericementitis. — An  intense  plastic  peri- 
cementitis, or  repeated  attacks  of  a  so-called  subacute  inflamma- 
tory process,  will  lead  to  a  new  formation  of  connective  tissue, 
cementum,  and  bone.  ISTew  formations  clue  to  a  distinct  inflam- 
matory process  are  termed  hyperplasia  or  hypertrophy,  in  dis- 
tinction from  those  new  formations  that  arise  without  prom- 
inent inflammatory  symptoms  and  are  generally  termed 
"tumors." 

Hyperplasia  of  pericementum  occurs  whenever  a  large  num- 
ber of  inflammatory  elements  are  newly  formed  and  remain  in 
connection  with  one  another,  thus  not  ceasing  to  be  a  tissue. 


472  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

The  inflammatory  elements  in  certain  districts  become  elong- 
ated, and,  after  having  split  into  narrow  spindles,  are  trans- 
formed into  a  solid  basis-substance,  which  means  a  new  forma- 
tion of  connective-tissue  bundles.  Such  bundles  differ  from 
those  of  normal  pericementum  in  their  greater  density  and 
their  very  irregular  arrangement.  H^-pertropbied  pericemen- 
tum is  occasionally  augmented  in  its  entire  bulk,  and  is  built 
up  of  coarse  bundles  of  connective  tissue,  between  which,  in  the 
earlier  stages  of  the  hyperplastic  process,  more  or  less  numer- 
ous nests  of  inflammatory  elements  are  still  seen.  In  other 
instances,  the  entire  pericementum  is  transformed  into  a  dense 
cicatricial  connective  tissue,  whose  bundles  are  very  small,  and, 
by  crossing  one  another  in  all  directions,  produce  a  feltwork. 
Hyperplastic  pericementum,  as  a  rule,  holds  fewer  blood-vessels 
than  the  normal. 

Sometimes  scattered  nests  of  the  inflammatory  elements 
exhibit  a  high  refracting  power,  which  evidently  is  due  to  a 
deposition  of  lime-salts  in  them,  the  so-called  calcification. 
This  process  is  entirely  different  from  ossification,  though  the 
former  apparently  precedes  the  latter.  Scattered  nests  of 
inflammatory  elements  may  be  transformed  also  into  clusters 
of  fat-granules,  which  are  recognizable  by  their  peculiar  refract- 
ing power,  and  by  remaining  unstained  by  either  carmin  or 
chloride  of  gold.  Irregularly-distributed  fat-globules  are  very 
often  seen  in  hyperplastic  pericementum.  Whether  these  glo- 
bules are  identical  with  the  original  fat-globules  in  normal  peri- 
cementum, or  are  formed  after  the  inflammatory  process  has 
abated,  I  am  unable  to  say. 

Localized  hyperplasia  of  the  pericementum  is  sometimes 
observed  at  the  neck  of  the  tooth,  in  the  shape  of  rather  broad 
nodules,  either  pediculated  or  sessile,  freely  vascularized,  and 
therefore  of  a  deep-red  color  to  the  naked  eye.  The  tissue  of 
such  a  nodule,  under  the  microscope,  appears  as  a  combination 
of  fibrous  and  myxomatous  connective  tissue,  richly  supplied 
with  capillary  blood-vessels.     (See  Fig.  237.) 

I^odules  of  this  type  are  allied  to  granulation-tissue,  the 
admixture  of  fibrous  bundles  being  attributable  to  the  original 
fibrous  structure  of  the  pericementum.  Such  nodules  are  prone 
to  penetrate  the  cementum  to  varying  depths.  Thej  cause  the 
appearance  of  pits  in  the  cementum  of  the  neck  of  the  tooth  as 
well  as  the  roots.     Often  they  are  transformed  into  pus  at  their 


MORBID    ANATOMY    OF    PERICEMENTITIS. 


473 


surface,  though  suppuration  is  seldom  profuse  in  this  form  of 
marginal  pericementitis.  Intense  suppuration,  combined  with 
formations  of  myxomatous  granulomata,  is  of  not  infrequent 
occurrence  along  the  root,  leading  to  an  almost  complete  pitted 
absorption  of  the  roots  of  the  affected  teeth.  This  process 
is  invariably  accompanied  by  intense  cementitis  and  eburnitis. 


Fig.  237. 


^  AX) 


^t^'i'i) 


r^Vt" 


(^. 


rc" 


"At 


i  \£i''ss 


m. 


w 


HYPEEPLAsriC  MTXOFIBEODb  PerICEMEML  M  CjRAMjLOMA  AT  THE  ^  ECK  OF  A  MOLAR. 

F,  F,  remnants  of  bundles  of  fibrous  connective  tissue  ;  M,  M,  myxomatous  granulation- 
tissue  between  the  fibrous  bundles  ;  C,  C,  capillary  blood-vessels  ;  P,  P,  zone  of  suppuration. 
Magnified  500  diameters. 

Xew  formation  of  cementum  is  observable  in  two  forms : 
either  as  re-formation  in  the  bay-like  excavations,  or  as  a  new 
formation  on  the  outer  surface  of  the  cementum. 

Re-formation  of  the  cementum  is  always  characterized  by  a 


474  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

deposition  of  lime-salts  in  the  territories  of  the  cement-corpus- 
cles, previously  dissolved  by  the  inflammatory  process.  The 
bay-like  excavations  remain  unchanged  in  their  configuration, 
even  after  new  cementum  has  formed.  The  difference  between 
normal  and  newly-formed  cementum  is  that  in  the  latter  cement- 
corpuscles  are  larger,  more  numerous,  and  irregular.  In  the 
basis-substance  we  not  infrequently  recognize  the  inflammatory 
elements  (osteoblasts),  the  infiltration  of  which,  first  with  a  gluey 
basis-substance,  afterward  with  lime-salts,  has  caused  the  new 
formation  of  cementum.  In  the  cementum  of  both  the  neck 
and  the  root  I  have  met  with  such  sharply-circumscribed  islands 
of  newly-formed  cementum,  apparently  with  no  connection  with 
the  outer  surface,  l^ay,  in  some  of  my  specimens  such  an  island 
has  formed  in  the  cementum,  covering  the  neck  of  the  tooth, 
and,  while  the  latter  shows  a  normal  structure,  and  is  devoid  of 
cement-corpuscles,  the  newly-formed  cementum  penetrates  the 
dentine  deeply,  and  exhibits  a  large  number  of  irregular  cement- 
corpuscles. 

The  inflammatory  new  formation  on  the  surface  of  the  cemen- 
tum appears  in  the  shape  of  either  a  continuous  layer  of  cement- 
tissue,  distinctly  bounded  toward  the  normal  cementum,  or 
jagged  on  the  outer  surface,  with  manifold  elongations  and 
erosions,  filled  with  newly-formed  connective  tissue.  Sometimes 
relatively  large  globular  formations  appear  on  the  outer  surface 
of  the  cementum  as  the  result  of  pericementitis. 

There  are  globular  bodies  in  connection  with  the  cementum 
by  means  of  a  pedicle,  which  closely  resemble  those  in  the  pulp- 
cavity  attached  to  the  dentine.  These  peculiar  formations  exhibit 
a  distinctly  concentric  lamination.  They  are  surrounded  by  a 
layer  of  spindle-shaped  medullary  elements,  and  hold  in  their 
centers  a  radiating  prot(^plasmic  mass,  resembling  a  bone-cor- 
puscle. As  to  their  origin,  there  can  be  scarcelj"  any  doubt  that 
they  arise  from  clusters  of  medullary  elements  or  multinuclear 
protoplasmic  bodies  as  above  described,  one  of  which  is  seen  in 
Fig.  238,  in  the  immediate  neighborhood  of  the  globular  forma- 
tion. "We  readily  understand  that  a  transformation  of  the 
medullar}^  elements  into  bony  basis-substance  will  lead  to  the 
formation  of  a  laminated  cement-globule;  the  difficulty  is  only 
to  understand  the  origin  of  the  central  protoplasmic  body. 
Perhaps  this  body  is  a  former  blood-vessel  solidified,  the  like  of 
which  we  can  often  trace  in  the  midst  of  a  multinuclear  proto- 


MORBID    ANATOMY    OF    PERICEMEXTITIS.  475 

plasmic  cluster.  All  new  formations  on  the  surface  of  the 
cementum  caused  by  an  inflammatory  process  may  be  properly 
denominated  "  exostoses  of  the  cementuna." 

I  have  repeatedly  seen  true  bony  new  formations  in  hyper- 
plastic pericementum.  They  appear  in  the  shape  of  irregular 
islands  or  elongated  spiculre  within  the  fibrous  connective  tissue, 
sometimes  so  near  to  the  cementum  that  no  doubt  is  left  about 
their  formation  in  the  midst  of  the  pericementum,  indepen- 
dently of  the  bony  alveolus.  These  formations  bear  a  close 
resemblance  to  embryonal  bone, — viz,  contain  a  large  number 


Globclar  Body,   Result  of  Pericementitis. 

G,  concentrically-striated  mass,  surrounded  by  small  spindle-shaped  elements,  holding  a  star- 
shaped  protoplasmic  body  in  its  center ;  C,  cementum  :  J/,  multinuclear  body,  so-called  myelo- 
plax,  from  which  a  globular  body  may  originate  ;  IE,  inflammatory  elements,  crowded  in  the 
pericementum.    Magnified  200  diameters. 

of  irregular  bone-corpuscles,  with  broad  offshoots,  and  a  relatively 
small  amount  of  bony  basis-substance. 

Lastly,  true  bony  new  formations  may  occur  on  the  wall  of 
the  alveolus,  which,  after  repeated  attacks  of  pericementitis,  as 
clinical  observation  teaches,  is  sometimes  supplied  with  thorny 
new  formations  of  bone.  These  exostoses  originate  on  the 
socket  of  the  tooth  from  the  medullary  tissue,  in  the  same 
manner  in  which,  exostoses  grow  on  any  other  bone  as  sec^uelse 
of  periostitis  and  osteitis.  In  the  highest  degree  of  development 
these  exostoses  of  the  socket  rej)lace  the  pericementum  to  such 


476  THE    ANATOMT    AND    PATHOLOGY    OF    THE    TEETH. 

an  extent  that  only  traces  of  the  pericementum  are  left.  Xo 
instance,  however,  at  least  to  my  knowledge,  has  been  observed 
of  a  complete  fusion  of  the  socket  with  the  tooth. 

Purulent  Pericementitis. — This  form  of  inflammation  is  invari- 
ably the  outcome  of  an  acute  process  with  supervening  infection 
with  staphylococci,  at  least  according  to  the  most  modern 
bacteriological  views.  The  invasion  is  explicable,  if  the  micro- 
organisms have  access  to  the  inflamed  pericementum  through  a 
carious  cavity  or  a  broken  root  of  a  tooth. 

Numerous  cases  are,  however,  on  record  in  which  teeth  with 
living  pulps  have  become  affected  by  suppurative  pericementitis. 
In  such  cases  we  surmise  that  the  staphylococci  were  carried  into 
the  pericementum  by  some  foreign  body  accidentally  pushed 
into  the  socket  below  the  gums  and  the  neck  of  the  tooth. 

The  possibility  cannot  be  denied  that  staphylococci  may 
circulate  temporarily  in  the  blood  and  then  settle  down  in  the 
inflamed  pericementum,  causing  suppuration. 

The  disease  is  either  acute  or  chronic,  and  may  appear  in 
either  of  these  forms  at  the  neck  of  the  tooth  as  marginal,  or  in 
a  limited  portion  of  the  pericementum  as  circumscribed,  or  at 
the  apex  of  the  root  as  apical  pericementitis  or  as  alveolar  abscess. 
The  first-named  form  is  usually  termed  pyorrhoea  alveolaris. 
Either  of  the  forms  named,  though  originally  limited  to  a  por- 
tion of  the  pericementum,  may  become  diffuse,  affecting  most 
of  the  tissue,  and  may  run  an  acute  or  a  chronic  course. 

Marginal  Purulent  Pericementitis  is  usually  termed  pyorrhea 
alveolaris.  In  this,  as  in  any  other  suppurative  process,  a  certain 
amount  of  the  tissue  involved  is  destroyed. 

Under  the  microscope,  the  first  stages  of  suppurative  perice- 
mentitis are  identical  with  those  of  the  plastic  form, — viz,  there 
are  nests  of  inflammatory  elements  between  bundles  of  unchanged 
connective  tissue.  (See  Fig.  232.)  The  less,  therefore,  of  this 
connective  tissue  is  left,  the  more  numerous  the  inflammatory 
elements  are,  the  nearer  is  the  tissue  to  suppuration. 

With  high  magnifying  powers  of  the  microscope  we  see 
that  the  inflammatory  process  goes  on  in  exactly  the  same  way 
as  in  plastic  pericementitis.  The  bundles  of  connective  tissue 
are  transformed  directly  into  inflammatory  elements,  which  at 
first  are  all  united  with  one  another.  This  union  of  the  inflam- 
matory elements  is  recognizable  in  relatively  large  nests  also,  in 
which  there  are  but  scanty  capillary  blood-vessels  left.     It  is 


MORBID    ANATOMY    Of    PERICEMENTITIS.  477 

only  after  the  mutual  connection  of  these  elements  is  broken 
that  the  bodies,  now  isolated,  deserve  the  name  of  pus-corpuscles, 
which  are  suspended  in  an  albuminous  fluid,  and  fill  a  cavity 
termed  an  "abscess."  This,  if  finding  exit  to  the  surface 
around  the  neck  of  the  tooth,  exhibits  the  typical  pyorrhoea 
alveolaris.  After  the  elimination  of  the  pus,  the  surrounding 
inflamed  tissue  grows  in  the  form  of  so-called  "  proud  flesh"  or 
granulations,  which  we  not  infrequently  meet  at  the  neck  as 
well  as  on  the  roots  of  teeth  extracted  during  an  attack  of  sup- 
purative pericementitis,  being  especially  well  developed  in  the 
bifurcations  between  the  roots  of  molars.  Such  granulations  are 
bailt  up  by  a  myxomatous  connective  tissue,  which  is  freely 
vascularized,  and  after  having  filled  the  cavity  of  the  abscess,  is 
transformed  into  dense  fibrous  connective  tissue.  Such  repara- 
tive tissue  is  termed  a  "  cicatrix."  Suppurative  pericementitis 
will  invariably  heal  by  cicatrization. 

The  morbid  anatomy  of  pyorrhoea  alveolaris  has  been  studied 
by  Wm.  H.  Atkinson*  on  the  teeth  of  a  cat,  his  conclusions 
being;  shown  in  the  folio  win  s^  abstract : 

"  Whether  suppuration  must  be  present  before  deposition  of 
lime-salts  can  only  be  settled  by  a  study  of  proper  micro- 
scopical specimens  in  the  very  earliest  stage  of  the  disease. 
The  deposit  was  formerly  called  tartar,  but  is  now  known  to  be 
a  deposit  of  lime-salts,  phosphate  of  lime,  with  some  carbonate 
of  lime,  entangled  with  leptothrix,  a  growth  which  is  rather 
common  around  the  teeth  of  almost  every  person.  If  a  speci- 
men be  placed  in  a  solution  of  chromic  acid,  the  lime-salts  will 
be  dissolved,  not  only  of  the  hard  tissues  of  the  tooth,  such  as 
dentine,  enamel,  and  cementum,  but  also  from  the  deposit  erro- 
neously called  tartar:  and  ultimately,  under  the  microscope, 
nothing  will  be  seen  but  aheap  of  leptothrix,  more  or  less  firmly 
attached  to  the  neck  of  the  tooth. 

"  In  one  specimen,  the  epithelial  covering  of  the  gums  has 
taken  a  bright  pink,  the  connective  tissue  a  pale  pink,  the  den- 
tine remaining  a  bright  green  from  the  reduction  of  the  chromic 
acid,  and  the  bone  of  the  socket  a  dark  green  for  the  same 
reason.  Blood-vessels  filled  with  blood  retained  their  original 
color,  not  being  affected  by  the  carmin.  I  have  to  add  that 
neither  the  horny  layer  of  the  epithelium  nor  the  growth  of 

*  Dental  Cosmos.  1888. 


478 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


leptothrix  has  been  influenced  by  tlie  carmin,  as  tliej^  retained 
a  slight  brownish-green  color.  All  micro-organisms  are  known 
to  resist  the  dye  of  carmin ;  whereas  they  eagerly  take  up  all 


Fig.   2^9. 


J^»li^^^yki 


Tempoeaey  Molar  of  a  Kitten  Six  Weeks  Old,  bHowiM,  ihe  Earlie&t  Stages 
OP  Pyorrhcea  Alyeolaris. 
P,  pulp-tissue  with  capillary  blood-vessels;  B,  bony  socket ;  C,  fibrous  connective  tissue, 
producing  upward  the  stroma  and  the  papillse  of  the  gum,  downward  the  pericementum  and  the 
periosteum  ;  E,  epithelium  ;  L^,  cluster  of  leptothrix  deprived  of  its  lime-salts  :  L-,  cluster 
of  leptothrix  upon  an  eroded  neck  of  tooth  and  entangled  with  pus-corpuscles  ;  A,  cavity  filled 
with  pus  in  continuity  with  the  pericementum.    Magnified  50  diameters. 

sorts  of  anilin  dyes.  Thus  a  single  specimen  shows  a  variety 
of  colors,  which  serves  as  assistance  for  the  discrimination  of 
otherwise  not  well-marked  tissues. 


MORBID    AXATOMY    OF    PERICEMEXTITIS. 


479 


"  For  low  powers  of  the  microscope,  just  suiScient  for 
obtaining  topographical  views,  a  molar  was  selected,  in  which 
the  features  I  am  abont  to  explain  are  beautifully  marked. 
(See  Fig.  239.)  The  specimen  is  taken  for  illustration  because 
on  one  side  of  the  neck  of  the  tooth  the  recession  of  the  gum 
and  the  growth  of  leptothrix  is  marked,  without  apparent  sup- 
puration; while  on  the  other  side  the  growth  of  leptothrix  has 

Fig.  240. 


Formation  of  Pes  from  Conxective  Tissue  axd  Epithelium  ix  Pyorehcea 
Alteolaris  of  a  KiTTEX  Six  Weeks  Old. 

-K,  epithelium  of  gum  with  proliferating  nuclei;  -ffP,  epithelium  in  transformation  to  pus- 
corpuscles  ;  P,  pus-corpuscles  sprung  both  from  epithelium  and  connective  tissue  ;  C,  connective 
tissue  of  gum  ;  B.  B,  blood-vessels  filled  with  corpuscles  ;  iV,  eementum  of  neck  of  tooth  :  B, 
dentine.    Magnified  600  diameters- 


led  to  marked  structural  changes  in  the  eementum  of  the  neck, 
in  the  epithelium  of  the  gum,  and  in  that  portion  of  the  peri- 
cementum in  contact  with  the  uppermost  portion  of  the  neck, 
which  by  anatomists  has  been  called  ligamentum  dentium. 


480  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

"  Xo  sign  of  trouble  below  the  pouch,  or  pocket,  is  seen  on 
the  right  side  of  the  specimen,  except  a  slight  hyperemia,  marked 
by  slightly-dilated  blood-vessels  tilled  with  blood-corpuscles.  We 
see  in  the  connective  tissue,  furnishing  the  papillae  as  well  as  the 
pericementum,  a  gradual  transition  from  basis-substance  to  pus- 
corpuscles.  At  first  the  connective  tissue  appears  granular; 
later  granular  or  solid  lumps  make  their  appearance;  and  at  last 
the  basis-substance  has  almost  completely  disappeared,  being 
replaced  by  a  number  of  so-called  inflammatory  corpuscles.  As 
soon  as  the  latter  become  isolated  they  represent  pus-corpuscles, 
which  invariably  are  intertwined  in  smaller  lumps  and  scattered 
granules,  probably  from  a  disintegration  of  some  pus-corpuscles. 
(Fig.  240.)  Here  we  observe  a  gradual  increase  of  the  living 
matter  of  the  epithelia  from  a  mere  division  or  splitting  of  the 
nuclei  to  a  considerable  increase  of  lumps  within  the  epithelia, 
and  to  their  breaking  up  into  isolated  lumps  or  corpuscles, — 
viz,  pus-corpuscles. 

"  In  epithelial  layers  the  cement-substance  between  epithelial 
bodies  holds  a  good  deal  of  living  matter  in  the  shape  of  con- 
necting filaments,  previously  termed  the  thorns.  Close  observa- 
tion shows  that  these  thorns  at  first  increase  in  bulk;  afterward 
coalesce  into  solid  cord-like  formations;  farther  on  swell  up  to 
pear-  or  club-shaped  formations,  which  themselves  split  up  into 
pus-corpuscles,  thus  adding  to  those  visible  in  an  abscess.  The 
pus-corpuscles  sprung  from  previous  epithelia  are  in  no  way 
difierent  from  those  originated  from  previous  connective  tissue. 

"  To-day  it  is  an  established  fact  that  suppuration  will  not  take 
place  either  in  connective  tissue  or  in  epithelium,  without  the 
presence  of  certain  micro-organisms  which  are  known  as  staphy- 
lococcus, or  Streptococcus  pyogenes  aureus,  albus,  or  citreus. 
It  is  a  great  question  yet  to  decide  whether  it  is  micro-organisms 
themselves  penetrating  the  protoplasm,  thus  inducing  disinte- 
gration of  the  tissue,  or  whether  it  is  the  chemical  product  of 
the  micro-organisms,  the  ptomaines,  that  induce  the  suppura- 
tion. However  this  may  be,  the  specimens  here  presented 
furnish  conclusive  proofs  that,  so  long  as  the  horny  or  pavement 
epithelium  is  present  as  a  protective  layer,  no  invasion  of  micro- 
cocci will  occur.  As  soon,  however,  as  this  protective  coat  is 
lost,  the  micro-organisms  may  penetrate  both  epithelium  and 
connective  tissue,  at  once  inducing  mischief. 

"  On  the  right  side  of  Fig.  239  the  pouch  between  the  tooth 


MORBID    ANATOMY    OF    PERICEMENTITIS. 


481 


and  the  gums  is  lined  all  around  by  flat  epithelia ;  there  is  a 
marked  hypersemia  of  the  connective  tissue,  but  no  marked 
inflammation  or  suppuration.  On  the  left  side,  on  the  contrary, 
the  pavement  epithelium  is  lost  at  the  bottom  and  the  sides  of 
the  pouch,  and  suppuration  has  started  at  once.  Whether  or 
not  the  growth  of  leptothrix  alone  is  sufficient  to  excite  inflam- 
mation or  suppuration  is  not  settled,  but  we  can  easily  conceive 

Fig.  241. 


Cejiextitis  induced  by  a  Grotvth  of  Leptothrix  ox  the  Neck  of  the  Tooth 
OF  A  Kitten  Six  Weeks  Old. 

X,  leptothrix  ;   C,  cementum  of  neck ;  D,  dentine  of  the  neck  destitute  of  canaliculi  ;   P,  pus 
partly  entangled  with  leptothrix.    Magnified  600  diameters. 


of  a  possibility  that  together  with  the  leptothrix  other  micro- 
organisms are  carried  along,  being  ready  for  the  invasion  of  the 
formed  tissues  as  soon  as  the  protective  horny  layer  is  lost. 

"  Attention  has  been  given  to  the  morbid  changes  of  the 
cementum  at  the  neck,  wherever  they  come  in  contact  with  the 
leptothrix.     (See  Fig.  241.) 

32 


482  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

"  Some  observers  claim  that  even  a  simple  inflammatory  pro- 
cess may  be  produced  by  the  presence  of  micro-organisms. 
This  assertion  I  am  not  able  to  sustain  from  the  study  of  my 
specimens,  or  any  that  I  have  seen.  True,  wherever  leptothrix 
has  encroached  upon  the  hard  tissues  of  the  tooth,  a  melting^ 
down  of  the  lime-salts  of  such  tissue  will  be  the  result.  In  the 
milder  forms  of  such  a  decalcification  (so-called)  we  observe  bay- 
like excavations,  partly  containing  isolated  protoplasmic  bodies,, 
clearly  the  offspring  of  the  perfected  tissue  present  even  in  tbe 
hard  tissues  of  the  tooth.  But  the  number  of  such  corpuscles 
is  never  sufficiently  large  to  warrant  the  diagnosis  of  inflam- 
mation; all  we  could  claim  is  a  reduction  of  the  hard  tissue 
into  soft  protoplasm,  probably  corresponding  to  a  juvenile  or 
embryonic  stage  of  that  very  tissue.  On  the  left  side  of  Fig. 
239  bay-like  excavations  are  discernible,  penetrating  not  only 
the  cementum  of  the  tooth,  but  also  the  dentine;  still,  there  is 
nowhere  a  symptom  of  inflammation  or  caries.  Here  our  micro- 
scopical finding  again  agrees  with  clinical  experience,  which 
teaches  us  that  in  pyorrhoea  alveolaris  the  exposed  roots  of  the 
teeth  very  rarely  become  carious,  usually  exhibiting  only  a 
slightly  roughened  surface." 

Alveolar  Abscess. — This  is  a  peculiar  form  of  suppurative 
inflammation  on  the  apices  of  the  roots  of  teeth. 

Examinations  of  microscopical  sections  through  the  root,  the 
socket,  and  the  alveolar  abscess,  demonstrate  that  the  latter  is 
either  unilocular  or  multilocular, — viz,  separated  into  two  or 
several  chambers,  all  filled  with  pus. 

In  acute  alveolar  abscess  both  the  main  wall  and  those  of  the 
compartments  are  crowded  with  inflammatory  corpuscles  to  such 
an  extent  that  with  low  powers  of  the  microscope  no  vestige  of 
the  original  fibrous  connective  tissue  of  the  pericementum  is 
recognizable.  At  the  periphery  of  the  inflamed  zone  we  see  a 
moderately-inflamed  layer  of  pericementum,  holding  a  variable 
number  of  brown  clusters,  obviously  remnants  of  extravasated 
blood,  verging  on  the  formation  of  pigment.  The  central  por- 
tion of  a  unilocular  alveolar  abscess  is  found  empty  the  same  as 
the  compartments  of  a  multilocular  abscess,  because  the  pus,  not 
being  a  tissue,  is  dragged  away  in  the  process  of  section-cutting, 
both  from  the  inflammatory  nests  of  the  pericementum  and 
from  the  contents  of  the  abscess-cavity.     iN'umerous  clusters  of 


MORBID    ANATOMY    OF    PERICEMENTITIS. 


483 


staphylococci  can  be  seen  with  higher  powers  of  the  microscope. 
(See  Fig.  242.) 

If  such  an  abscess  has  existed  for  several  weeks  or  months, 
it  becomes  chronic,  and  then  the  aspect  under  the  microscope 
is  different  from  that  seen  in  the  acute  stage.     As  a  rule,  the 

Fig.  242. 


Acute  Alveolar  Abscess.— Ixcipiext  Suppuration  i\  Compartments. 

C  compartments  from  which  the  pus  has  been  removed  by  the  microtome  ;  Z"^,  outermost 
zone,  the  moderately-inflamed  pericementum ;  Z-,  middle  zone,  the  intensely-inflamed  perice- 
mentum ;  Z^,  zone  in  approaching  suppuration.    Magnified  100  diameters. 


walls  of  the  compartments  have  perished  by  being  transformed 
into  pus.  A  chronic  abscess,  therefore,  will  usually  appear 
unilocular. 

The  tissue  bordering  directly  upon  the  abscess  is  a  broad 


484 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


layer  of  the  myxomatous  type,  intermixed  with  delicate  bundles 
of  fibrous  connective!  tissue.  In  this  layer  a  scanty  number  of 
newly-formed  capillaries  are  met  with.     (See  Fig.  243.) 

This  layer  has  been  overlooked  by  previous  observers,  and 
even  Yirchow  termed  it  "  crude  pus."  To-day  we  know  that 
it  is  just  the  myxomatous  tissue  which  at  its  innermost  portions 

Fig.   243. 


Wall  of  Chronic  Alveolar  Abscess. 

M,  myxomatous  portion  of  wall ;  F,  fibrous  portion  of  wall  (so-called  membrana  pyogena) ; 
P,  periosteum  slightly  inflamed  :|IC,  pus-cavity,  pus-corpuscles  removed  by  section-cutting. 
Magnified  100  dianr.eters.5  s 

breaks[up  into  pus-corpuscles,  thus  augmenting  the  size  of  the 
pus-cavity.     (See  Fig.  244.) 

We  know  also  that  after  the  evacuation  of  the  pus  it  is  the 
myxomatous  layer  which,  by  a  luxuriant  growth,  furnishes  the 
richly-vascularized  granulation-tissue. 


MORBID    ANATOMY    OF    PERICEMEXTITIS. 


485 


At  the  periphery  of  the  myxomatous  wall  of  the  abscess  we 
notice  a  dense  layer  of  newly-formed  fibrous  connective  tissue, 
the  wall  proper  of  the  abscess,  which  by  old  surgeons  was 
termed   "  membrana    pyogena."      That   this    layer  is   newly 


Fig.  244. 


||s^l^ 


'''M 


IxNEBMOST  Portion"  of  Wall  of  Abscess.    MTxoiiATOtrs  Tissue. 

5,  i?,  partly  protoplasmic,  partly  fibrous  reticulum;  B,  B,  myxomatous  basis-substance  ; 
P,  P,  protoplasmic  bodies  in  various  stages  of  development ;  C,  capillary  blood-vessel.  Mag- 
nified 500  diameters. 


formed,  appears  clearly  from  the  fact  that  its  bundles  run  a  con- 
centric course  around  the  abscess,  noticeably  different  from 
those  of  the  original  pericementum,     (See  Fig.  243.) 

As  a  matter  of  course,  an  intense  purulent  pericementitis  will 
easily  affect  the  periosteum.     It  is  not  infrequent  that,  owing 


486  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

to  complete  destruction  of  the  blood-vessels  of  the  periosteum 
and  the  medulla,  serving  for  the  nutrition  of  the  bone,  this 
latter  becomes  necrotic.     (See  chapter  on  JSTecrosis.) 

When  the  inflammatory  process  has  lasted  for  months,  the 
newly-formed  connective  tissue  assumes  a  distinct  fibrous  struc- 
ture, and  between  the  bundles  there  are  interspersed  nests  ot 
inflammatory  elements.  These  may  be  partly  transformed  into 
fat-granules,  or  produce  opaque  laj'ers  in  fatty  degeneration. 
If,  on  the  contrar}^,  the  alveolar  abscess  be  of  a  more  recent 
date,  the  fibrous  structure  of  the  sac  is  plainly  marked  on  its 
periphery  only,  while  the  central  portions  bear  the  character  ot 
a  myxomatous  granulation-tissue.  The  strings  or  the  septa, 
traversing  the  abscess,  may  eventually,  in  accordance  with  the 
duration  of  the  disease,  be  found  either  of  a  fibrous  or  myxo- 
matous structure.  In  both  instances  we  often  meet  with  a  large 
number  of  newly-formed  capillary  blood-vessels.  The  inner 
surface  of  the  sac  is  not  smooth,  but  largely  provided  with 
irregular  protrusions,  or  papillary  outgrowths  of  a  myxomatous 
structure,  crowded  with  inflammatory  elements.  The  sac  con- 
tains inspissated  pus,  which,  upon  the  cutting  of  microscopical 
sections,  crumbles  away. 

Cementitis  and  osteitis  always  accompany  an  alveolar  abscess. 
Cementitis  leads  to  a  destruction  of  the  cementum  in  the  shape 
of  deep,  irregular,  bay-like  excavations,  which  exhibit  all  stages, 
from  the  liquefaction  of  the  basis-substance  up  to  the  trans- 
formation of  the  living  matter  into  pus-corpuscles.  Sometimes 
the  excavations  penetrate  the  dentine.  In  the  highest  degrees 
of  pericementitis  the  apex  of  the  root,  inclosed  in  the  alveolar 
abscess,  is  transformed  into  a  thin,  jagged,  and  corroded  stump, 
with  but  scanty  remnants  of  the  former  cementum. 

Osteitis  (inflammation  of  the  wall  of  the  alveolus)  is  an  inevit- 
able result  of  the  formation  of  an  alveolar  abscess.  The  portion 
of  the  socket  in  contact  with  the  sac  of  the  abscess  is  widened, 
its  surface  being  either  smooth  or  jagged.  Examination  with 
the  microscope  leaves  no  doubt  that  the  inflammatory  elements, 
sprung  from  the  bony  tissue  after  dissolution  of  its  lime-salts 
and  liquefaction  of  its  gluey  basis-substance,  become  spindle- 
shaped,  and  share  largely  in  the  formation  of  the  wall  of  the 
abscess. 

In  higher  degrees  of  osteitis  the  wall- of  the  alveolus  is  re- 
duced to  irregular,  eroded  trabecular  of  bone,  the  outer  surface 


MORBID    ANATOMY    OF    PERICEMENTITIS. 


487 


of  which  is  lined  by  a  dense,  newly-formed  connective  tissue, 
identical  with  that  of  the  wall  of  the  abscess.  The  neighboring 
medullary  spaces  are  enlarged  and  crowded  with  inflammatory 
elements. 

Considerable  interest  attaches  to  the  healing  process  of  peri- 

FiG.  245. 


pMm$f:^^]00M0^^^^f 


Healing  Process  of  Peeickmextitis  axd  Cementitis. 

P,  pericementum  consisting  iof  newly -formed  fibrous  connective  tissue;  B,  border  of 
cementum  with  bay -like  excavations ;  T,  zone  of  cementum  with  faintly-marked  territories ; 
G,  unchanged  cementum ;  /,  /,  islands  of  territories  of  cementum ;  M,  medullary  space. 
Magnified  400  diameters. 

cementitis  and  cementitis,  such  as  we  are  able  to  observe  in 
chronic  alveolar  abscess,  after  the  subsidence  of  the  inflamma- 
tory symptoms.  (See  Fig.  245.)  We  observe  a  transformation 
of  the  inflamed  pericementum  into  irregular  tracts  of  fibrous 


488  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH, 

connective  tissue,  still  plentifully  supplied  with  globular  and 
spindle-shaped  protoplasmic  bodies.  In  this  tissue  we  find 
inclosed  irregularly  recalcified  territories  of  cementum,  with 
faintly-marked  central  cement-corpuscles.  The  border-zone  of 
the  cement  is  conspicuous  by  its  deep,  bay-like  excavations, 
filled  with  newly-formed  pericementum.  At  some  distance 
from  the  border,  the  outlines  of  the  recalcified  territories  of  the 
cement-corpuscles  are  still  recognizable.  In  this  zone  we  notice 
apparently  isolated  medullary  spaces,  which  probably  are  in 
continuity  with  the  surface  of  the  cementum  and  have  escaped 
recalcification.  After  the  accomplishment  of  the  latter  process, 
the  cement-corpuscles  have  resumed  their  original  shape, 
though  many  of  them  appear  a  trifle  larger  and  more  irregular 
than  the  original  cement-corpuscles. 


CHAPTER   XL. 

CARIES    OF    THE    TEETH. 


The  modern  views  in  regard  to  the  origin  of  caries  of  the 
teeth  are  based  upon  bacteriological  researches.  Previous  to 
1882,  before  bacteriology  became  a  systematized  science,  the 
origin  of  caries  was  thought  to  be  a  mere  decalcification  of 
enamel  and  dentine,  accompanied  by  a  growth  of  micro-organ- 
isms. But  even  at  that  time  much  valuable  work  was  accom- 
plished. The  proof  that  the.  living  tissues  of  the  teeth,  if 
attacked  by  the  process  of  caries,  react  by  an  inflammatory 
process,  was  then  a  great  step  in  advance,  a  fact  which  has 
altogether  been  neglected  by  bacteriologists.  In  order  to  do 
justice  to  both  parties,  I  deem  it  advisable  to  give  the  views 
held  by  Frank  Abbott^^  and  those  announced  by  W.  D.  Miller, 
of  Berlin. f  The  former  was  published  in  ante-bacteriological 
times,  the  latter  is  founded, entirely  on  bacteriological  research. 
I  am  convinced  that  only  by  a  combination  of  both  the  inflam- 
matory and  the  bacteriological  doctrines  the  full  truth  will  be 
reached. 

*  Dental  Cosmos,  1879. 

t  "  The  Micro-Organisms  of  the  Human  Mouth,"  1890. 


CARIES  OF  THE  TEETH.  489 

Frank  Abbott's  Views.* — "  Etiology. — The  first  lesion  under 
all  circumstances  is  due  to  the  action  of  an  acid,  which  in  a 
merely  chemical  way  dissolves  out  the  lime-salts  from  the 
enamel.  No  doubt  quite  a  strong  acid  is  necessary  for  decalci- 
fication of  so  solid  a  tissue  as  the  enamel  of  a  tooth.  And  the 
question  next  arises,  Where  does  this  acid  come  from  ? 

"  First  let  us  take  into  consideration  the  starting-points  of  the 
morbid  process.  I  fear  no  contradiction  on  the  part  of  my  pro- 
fessional brethren  when  I  say  caries  never  begins  on  the  smooth 
surfaces  of  a  tooth,  which  are  exposed  to  the  friction  of  masti- 
cation, but  always  starts  on  points  which,  owing  to  their  ana- 
tomical structure,  form  receptacles  for  food,  etc.,  or  on  points 
between  the  teeth  where,  owing  to  want  of  cleanliness,  decaying 
miaterial  can  accumulate.  It  is  therefore  not  to  the  friction 
between  the  single  teeth  (Salter),  which,  as  we  know,  is  possible 
to  a  certain  extent  in  the  normal  condition,  but  to  the  acid 
generated  from  the  decaying  material  retained  between  the  two 
flat  or  concave  surfaces  which  the  teeth  present  to  each  other, 
that  the  beginning  of  the  destruction  of  enamel  is  due. 

"  That  this  decaying  material  may  be  sought  for  and  found  in 
the  food,  I  think  will  hardly  admit  of  a  doubt;  and,  as  it  occurs 
to  me,  mainly  in  such  kinds  of  food  as  through  their  decompo- 
sition are  apt  to  produce  an  acid,  not  very  strong,  perhaps,  in 
itself,  bat  possessing  a  high  degree  of  afiinity  for  lime-salts, — 
viz,  lactic  acid. 

"  First  among  the  varieties  ot  food  ranks  meat,  which  by 
putrefaction  may  produce  free  lactic  acid ;  next  are  the  sac- 
charine materials ;  and  last  the  amylaceous,  which  being  con- 
verted into  dextrine  by  the  action  of  the  saliva,  may  be  trans- 
formed, if  brought  in  contact  with  putrefying  meat,  into  lactic 
acid.  There  is"  no  doubt  that  the  organic  portion  of  teeth, 
as  it  advances  to  the  stage  of  decomposition  in  the  process  of 
caries,  plays  a  very  important  part  in  the  formation  of  this  acid. 

"  Perhaps  the  sour  decomposition  is  assisted  locally  by  the 
action  of  micrococci  and  leptothrix;  although  these  organisms 
are  known  to  prosper  only  in  alkaline,  and  not  in  acid  fluids. 
These  vegetable  organisms  are  present  in  innumerable  quanti- 

*  This  was  first  published  in  1879.  Professor  Ahhott  has  been  kind  enough  to 
furnish  me,  especially  for  this  book,  with  his  present  views,  as  expressed  in  the 
conclusions  of  his  original  paper  The  headings  I,  II.  and  III  of  the  results  of 
his  studies  are  chana;ed  bv  himself. 


490  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

ties  on  the  healthiest  gum ;  tartar  is  crowded  with  them.  And 
even  in  the  highest  degrees  of  development  of  tartar  caries  is 
absent.  In  fact,  when  decayed  cavities  in  the  teeth  become 
filled  with  tartar,  the  carious  process  is  as  effectually  stopped  as 
it  is  possible  for  it  to  be  when  such  cavities  a.re  Jilled  in  the  most 
perfect  manner  with  gold  or  any  other  favorite  material.  Hence 
I  do  not  consider  the  views  of  those  authors  correct  who  claim 
that  micrococci  and  leptothrix  play  any  important  part  in  pro- 
ducing, or  even  supporting,  the  carious  process. 

"  I  fully  concur,  however,  with  the  views  of  those  who  claim 
that  the  resistance  of  the  teeth  against  caries,  owing  to  their 
amount  of  lime-salts,  greatly  varies  in  different  people.  The 
hue  of  the  teeth,  as  is  well  known,  is  indicative  to  some  extent 
of  their  amount  of  lime-salts.  The  microscope  shows  a  con- 
siderable variety,  vdih  regard  to  the  presence  or  the  degree  of 
density,  of  that  layer  of  the  basis-substance  surrounding  the 
dentinal  canaliculi.  E.  Neumann  first  drew  attention  to  this 
layer,  which  sometimes  is  so  dense  and  so  well  defined,  owing 
to  its  greater  refracting  power  than  that  of  the  basis-substance 
between  the  canaliculi,  that  it  may  be  regarded  almost  as  a 
protecting  sheath  to  the  living  matter  -within  the  canaliculi. 
This  layer  is  well  marked  even  in  fossil  teeth ;  it  resists  some- 
what the  action  of  strong  acids  and  alkalies,  but  it  is  almost 
completely  absent  in  a  number  of  carious  teeth  which  I  have 
examined.  I  have  also  remarked  that  difierent  teeth,  treated 
exactly  in  the  same  manner  with  chromic-acid  solution,  become 
soft  in  a  markedly  shorter  space  of  time  than  others.  The 
general  health  or  constitution  may  have  considerable  influence 
upon  the  quantity  of  lime-salts  deposited  in  the  basis-substance 
of  the  teeth. 

"  Nations  of  high  civilization,  which  inevitably  leads  to  bodily 
and  mental  depravation,  as  a  rale  have  a  greater  percentage  of 
carious  teeth  than  those  of  a  low  degree  of  culture,  or  with  no 
culture  at  all. 

"  However  this  may  be,  the  fact  that  caries  of  the  teeth  begins 
as  a  chemical  process  scarcely  will,  in  my  opinion,  be  ques- 
tioned. On  a  dead  tooth,  natural  or  artificial,  as  well  as  on 
teeth  manufactured  from  the  dentine  of  the  elephant  or  the 
hippopotamus,  the  process  will  remain,  under  all  circumstances, 
a  chemical  one,  assisted  only  by  the  putrefying  remains  of  the 
organic  material  of  the  tooth;  while  on  a  live  tooth  either 


CARIES    OF    THE    TEETH.  491 

acute  or  chronic  reaction-changes  take  place,  which  I  intend 
presently  to  consider. 

^^  Caries  of  Enamel. — The  clinical  phenomenon  of  caries,  in 
its  very  origin,  consists  essentially  in  a  discoloration  of  the 
enamel.  A  Avhitish  or  grayish  spot  on  the  surface  of  the 
enamel  is  indicative  to  an  experienced  eye  of  the  beginning  of 
decay,  which  spot  proves,  when  touched  with  an  instrument, 
to  be  soft  and  crumbly.  Often  a  brown  spot  is  \^sible  on  the 
enamel  as  a  sign  of  the  softening  process.  The  less  pigmen- 
tation present,  the  more  rapid  is  the  process  of  decay.  On  the 
contrary,  the  more  distinct  the  discoloration,  the  slower  is  the 
softening  process,  l^ay,  dark-brown  spots  may  be  present  in 
the  enamel  for  many  years  without  being  followed  by  softening. 
The  brown  discoloration,  as  such,  cannot  be  considered  as  an 
essential  feature  of  caries  of  enamel,  but  it  usually  accompa- 
nies the  carious  process,  and  does  so  the  surer  the  slower  the 
morbid  process  runs.  On  microscopic  specimens  we  meet  with 
decayed  pits  in  enamel  without  any  discoloration  of  this  tissue. 
On  other  specimens  we  have  a  very  marked  orange  or  brown 
hue  on  the  decayed  part  as  well  as  in  its  neighborhood,  and 
sometimes  scattered  specks  are  to  be  seen  some  considerable 
distance  from  the  diseased  part.  The  brown  discoloration  is 
located  in  the  basis-substance  of  the  enamel-rods,  the  outlines 
of  which  are  much  more  marked  than  when  in  a  healthy  condi- 
tion. The  interstices  between  the  rods  here  are  plainly  visible 
even  with  a  magnifying  power  of  only  500  diameters.  This 
power  will  reveal  delicate  beaded  fibers  of  living  matter  within 
the  interstices,  which  in  healthy  enamel  can  be  seen  distinctly 
with  a  power  of  800  to  1000  only.  Besides  the  discoloration, 
no  material  changes  are  seen  in  the  enamel-rods. 

"  What  process  the  pigmentation  of  the  enamel  is  due  to  I 
cannot  say,  but  it  occurs  to  me  that  we  have  no  right  to  look 
upon  this  process  as  a  merely  chemical  reaction  upon  the  basis- 
substance  of  the  rods.  That  in  fact  it  is  the  basis-substance 
holding  the  pigment,  and  not  the  lime-salts  deposited  therein, 
is  proven  by  specimens  from  which  the  lime-salts  have  been 
extracted  to  a  considerable  extent  by  chromic  acid,  and  which 
still  show  the  brown  stain.  I  dare  say  that  this  brown  dis- 
coloration is  a  strong  proof  of  the  presence  of  life  in  the 
enamel,  as  in  teeth  where  the  pulps  are  dead  such  stains  never 
appear,  nor  can  they  be  produced  by  artificial  means.     The 


492 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


process  of  decay  in  the  enamel  can  best  be  studied  on  superficial 
erosions  of  the  same,  a  sample  of  which  I  have  illustrated.  In 
this  instance  the  brown  discoloration  of  the  decayed  part  was 
but  trifling,  and  entirely  absent  in  its  vicinity,  so  that  we  have 
to  consider  it  as  a  case  of  acute  caries. 

"  We  see  at  E,  Fig.  246,  the  unchanged  enamel  partly  de- 
prived of  its  lime-salts.  Toward  the  periphery  a  zone  appears 
in  which  the  enamel-rods  are  spotted,  evidently  owing  to  their 
partial  decalcification.  Close  to  this  and  immediately  below 
the  decayed  part  a  zone  is  visible  in  which  the  enamel  is 
granular,  and  looks  precisely  like  normal  enamel  from  which, 


Fig.  246. 


-t.  t  ^ -i  ^ea  m?---^mm-^si 


Acute  Caeies  of  Enamel. 

E,  unchanged  enamel;  S,  enamel  deprived  of  its  lime-salts;  M,  enamel  broken 
medullary  corpuscles ;  D,  medullary  corpuscles  indistinctly  marked ;  N,  flat  epithelia. 
fied  1000  diameters. 


down  to- 
Magni- 


by  a  somewhat  stronger  solution  of  chromic  acid,  the  lime-salts 
have  been  dissolved  out.  Here  the  protoplasmic  condition  of 
the  enamel  is  re-established  simply  by  disorganization,  and 
there  is  no  doubt  that  this  is  the  very  condition  of  the  enamel 
by  which  the  white  spot  is  produced  upon  the  surface  while  the 
tooth  is  still  in  the  jaw.  On  the  boundary  of  the  enamel 
we  see  a  shallow  depression  filled  with  protoplasmic  bodies, 
which  represent  either  complete  enamel-prisms  or  lumps  of 
such  prisms.  All  these  protoplasmic  formations  are  united 
with  one  another  by  delicate  threads;  they  exhibit  but  a  slight 


CARIES    OF    THE    TEETH.  493 

"brown  discoloration,  they  readily  imbibe  carmin,  and  if  the 
specimen  be  stained  with  a  half  per  cent,  solution  of  chloride 
of  gold  these  bodies  assume  a  dark-blue  tinge,  while  the 
unchanged  enamel  is  but  little  affected  by  this  reagent.  On 
the  outermost  layer  we  see  several  flat  epithelial  bodies 
attached  to  the  protoplasm,  which  in  the  transverse  section 
look  irregularly  spindle-shaped,  and  are  evidently  the  remnants 
of  the  so-called  !N"asmyth's  membrane,  or  enamel-cuticle, 
sunken  down  with  the  decaying  protoplasm.  On  the  level  of 
the  enamel  we  also  recognize  such  flat  epithelia.  Beneath 
them  on  the  right  side  of  the  drawing  there  is  present  a  zone 
of  decalcified  enamel,  while  on  the  left  side  the  division  into 
protoplasmic  bodies  is  fnlly  accomplished. 

"  ISTot  a  trace  of  micrococci  or  of  leptothrix  is  visible  in  or 
above  the  decayed  pit  of  the  enamel,  which  again  proves  that 
these  organisms  do  not  play  any  important  part  in  the  process 
of  caries ;  at  least,  do  not  materially  interfere  with  the  tooth  in 
its  normal  condition. 

"  The  way  in  which  the  caries  proceeds  downward  is  plainly 
shown  by  the  figure.  There  are  small,  irregular,  bay-like 
excavations  on  its  boundary,  and  in  the  midst  of  the  decayed 
part  a  wedge-shaped  elongation  is  running  downward  into 
the  softened  enamel.  The  shape  in  which  caries  appears  in 
the  enamel  is,  however,  greatly  varj'ing.  Besides  the  wedge 
shape  as  illustrated  in  the  figure,  the  forms  in  which  caries  pro- 
ceeds are  shallow  or  conical  excavations,  with  abrupt  walls, 
fissures,  and  grooves.  On  the  bottom  of  the  main  excavation 
we  sometimes  see  a  smaller  cavity,  it  being  in  a  narrow  or 
ivide  communication  with  the  main  decayed  mass. 

"  Besides  the  peculiar  medullary  elements  forming  the  con- 
tents of  a  carious  cavity  of  the  enamel  in  its  initial  stage,  I  not 
very  rarely  have  met  with  dark-brown,  irregularly-shaped  clus- 
ters filling  the  whole  cavity.  How  such  changes  of  medullary 
corpuscles  are  produced  I  am  unable  to  say,  although  it  seems 
to  be  kindred  to  the  so-called  colloid  or  hyaloid  metamorphosis 
which  we  observe  in  other  tissues,  the  only  difference  being 
that  in  caries  the  colloid  clusters  are  deeply  saturated  with  a 
uniform  brown  pigment,  the  origin  of  which,  as  mentioned 
above,  is  unknown. 

"  Caries  of  Dentine. — Upon  examining  a  large  number,  of 
i;eeth  with  carious  dentine,  we  are  struck  by  conditions  to  the 


494 


THE    ANATOMY    A^D    PATHOLOGY    OF    THE    TEETH. 


presence  of  which  no  observer  has  as  yet  drawn  attention. 
Sometimes  the  dentine,  attacked  by  caries,  looks  but  little 
changed  on  its  periphery.  A  narrow  zone  of  yellowish  color 
forms  the  boundary  toward  irregular,  shallow  excavations  (see 
Fig.  247).  At  other  times,  besides  the  bay-like  excavations  on 
the  periphery,  there  are  visible  elongations,  cylindrical,  conical, 
pear-shaped,  or  leaf-like,  passing  down  into  the  dentine  in 
varying  depths  (see  Fig.  247,  0).  There  is  no  doubt  that  this 
form  of  decay  of  the  dentine  occurs  with  the  least  preliminary 
changes  of  the  tissues;  it  evidently  runs  a  slow  course,  and  I 
think  I  am  justified  in  calling  this  form  of  caries  chronic.  It 
seems  evident  that  decay  of  a  tooth  assumes  an  acute  or  chronic 
form  just  in  proportion  to  its  perfect  or  imperfect  calcification. 


Chronic  Caries  of  Dentine. 

jD,  dentine  ;  0,  the  process  of  decay  penetrating  into  dentine  in  the  shape  of  short  offshoots  ; 
C,  decayed  mass.    Magnified  200  diameters. 


Dead  teeth  in  which  the  pulps  have  been  destroyed  either  by 
necrosis  as  a  natural  process,  or  by  artificial  means  with  caus- 
tics, very  frequently  run  this  kind  of  slow  or  chronic  decay. 
The  decay  of  artificial  teeth,  either  human  or  ivory,  in  all 
probability  runs  either  an  acute  or  a  chronic  course,  according 
to  the  amount  of  lime-salts  infiltrated  into  the  glue-yielding 
basis-substance. 

"  I  have  examined  a  piece  of  a  hippopotamus  tooth  which,  for 
a  period  of  about  one  year,  was  worn  in  the  mouth  of  a  patient^ 
and  a  spot  became  decayed  about  the  size  of  a  hemp-seed.  I 
softened  this  piece  with  chromic-acid  solution,  imbedded  it  in 
paraffin  and  wax,  and  cut  thin  sections  with  a  razor.  On  the 
bottom  of  the  decayed  pit  numerous  conical  spots  appeared 


CARIES    OF    THE    TEETH.  495 

runnino;  downward  into  the  dentine,  characterized  by  the 
absence  of  coloring-matter  in  specimens  stained  with  carmin. 
No  material  change  besides  was  observable ;  even  the  dentinal 
canaliculi  did  not  look  enlarged.  The  bottom  of  the  carious 
cavity  was  covered  with  a  layer  of  finely-granular,  evidently 
disintegrated  organic  material,  and  above  this  the  ordinary 
masses  filling  carious  cavities  in  teeth, — viz,  micrococci  and 
leptothrix, — were  visible. 

"  In  chronic  caries  merely  a  chemical  process  takes  place, 
assisted  by  putrefaction  of  the  organic  constituents  of  the  tooth. 
Here  first  the  solution  of  the  lime-salts  of  the  dentine  takes 
place,  either  along  the  bay-like  excavations  or  in  the  shape  of 
longitudinal  depressions.  No  reaction  whatever  follows  this 
process.  The  glue-yielding  basis-substance  being  deprived  of  its 
lime-salts  shows  a  yellow  discoloration,  and  only  traces  of  the 
dentinal  canaliculi.  The  basis-substance  then  breaks  down  into 
an  indistinct  granular  mass,  which  is  immediately  filled  with  a 
new  growth  of  low  vegetable  organisms, — viz,  micrococci  and 
leptothrix. 

"  My  specimens  plainly  show  that  these  organisms  are  not  the 
advance  guard  in  the  process  of  decay.  The  first  change  that 
takes  place  is  exposure  of  the  basis-substance  by  the  chemical 
action  of  some  acid,  independent  of  the  named  organisms,  which 
come  to  \\ew  only  after  complete  disintegration  of  the  basis- 
substance.  I  never  have  seen  the  penetration  of  these  organisms 
into  the  dentinal  canaliculi  before  a  thorough  decalcification  of 
the  basis-substance  had  taken  place.  No  doubt,  however,  the 
decayed  mass  itself  may  be  crowded  with  such  organisms  which 
they  seem  to  form  with.  In  the  great  majority  of  my  specimens 
I  have  met  with  formations  on  the  diseased  boundary  of  the  den- 
tine which  demonstrate  a  considerable  degree  of  reaction,  pro- 
duced by  the  irritating  power  of  the  same  agent,  to  which  the 
lime-salts  of  the  dentine  yield.  In  fact,  this  was  the  case  in  all 
teeth  which  were  alive  when  attacked  by  the  carious  process,  or 
rather  when  removed  from  the  jaws.  On  the  boundary  of  this 
process  we  see  irregularly-shaped  elongations  running  a  certain 
depth  into  the  tissue  of  the  dentine.  The  more  superficial  the 
elongations  are,  the  surer  the  morbid  process  may  be  termed  a 
slow  one  ;  and,  on  the  contrary,  the  deeper  the  elongations,  the 
more  certain  we  may  be  that  the  morbid  process  has  advanced 
rapidly.     The  elongations  mainly  have  the  shape  of  fissures 


496 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


filled  with  a  dark  granular  material,  if  viewed  with  a  low  power. 
These  fissures  run  independently  of  the  direction  of  the  dentinal 
canaliculi;  nay,  very  often  cross  them.  (See  Fig.  248.)  In 
the  specimens  they  look,  as  a  rule,  as  if  communicating  with 
each  other,  and  also  directly  or  indirectly  with  the  decayed  outer 
surface.  Sometimes  the  fissures  appear  completely  isolated, 
though  we  may  assume  that  they  are  separated  from  the  com- 
munication with  analogous  and  more  superficial  formations  only 
by  the  method  of  preparation, — viz,  cutting  into  thin  lamellae. 
"  On  the  surface  of  the  carious  portion  of  dentine  we   see 

Fig.  248. 


E,  E,  fissures  in  which  the  decay  penetrates  into  the  dentine ;  /,  small  islands  of  unchanged 
dentine.    Magnified  200  diameters. 


irregular  cavities  filled  with  the  same  granular  mass  that  is 
present  in  the  fissures,  consisting  evidently  of  debris  of  the 
former  tissue,  together,  perhaps,  with  micrococci,  and  very  often 
fine  thread-like  leptothrix.  The  more  rapidly  the  destruction 
of  the  dentine  has  advanced,  the  more  irregular  islands  of 
•dentine  are  left  on  the  surface. 

"  In  our  figure  the  decay  evidently  has  proceeded  rapidly ; 
hence  the  remnants  of  the  former  dentine,  recognizable  by  the 
presence  of  the  canaliculi,  are  very  small  and  irregular  on  the 
outer  periphery  of  the  dentine. 


CARIES  OF  THE  TEETH.  497 

*' The  outermost  portion  of  the  decayed  part  is,  as  a  rule, 
biittle,  and  crumbles  awaj  m  chromic-acid  specimens.  Where 
it  is  left  it  shows  a  crowd  of  leptothrix  and  micrococci,  without 
any  distinctly  recognizable  remnants  of  the  former  tissue.  On 
the  boundary  of  the  carious  portion  we,  as  mentioned  above, 
meet  with  a  yellow  discoloration  of  the  dentine,  evidently  pro- 
duced by  an  inflammatory  reaction,  which  lirst  breaks  down  the 
organized  constituents  of  the  lime-salts  and  in  turn  liquefies  the 
glue-yielding  basis-substance.  In  live  teeth  the  yellow  discolora- 
tion usually  takes  place  in  the  shape  of  longitudinal  strings  of 
different  diameters,  running  mainly  parallel  with  the  longi- 
tudinal direction  of  the  dentinal  canaliculi.  ISTay,  we  often  see 
single  yellow  strings  running  from  the  bottom  of  a  carious  cavity 
in  the  enamel  through  the  whole  depth  of  the  dentine  to  the 
pulp-chambers.  (See  Fig.  248,  jE",  -E'.)  The  best  method  for 
demonstrating  these  strings  is  doubtless  the  staining  of  chromic- 
acid  specimens  in  an  ammoniacal  solution  of  carmin.  "While 
the  unchanged  dentine  readily  takes  up  the  carmin,  the  strings, 
the  deep  yellow  color  of  which  is  undoubtedly  due  to  the  action 
of  the  chromic  acid,  remain  unstained. 

"With  a  power  of  about  five  hundred  diameters,  we  recog- 
nize under  the  microscope,  in  longitudinal  section  of  the  dentine, 
that  sometimes  the  yellow  discoloration  has  taken  place  only 
within  the  limits  of  a  few  dentinal  canaliculi,  while  at  other  times 
quite  a  number  of  these  have  undergone  discoloration.  Still 
sharper  defined  is  the  yellow  discoloration  in  transverse  sections. 
Here  we  see  that  mainly  the  canaliculi  and  their  immediate 
neighborhood  have  taken  up  the  yellow  color  in  the  shape  of 
sharply-circumscribed  dots,  which  are  the  larger  the  nearer  they 
approach  to  the  peripher}^  of  the  decayed  part.  The  basis-sub- 
stance between  these  yellow  spots  has  taken  up  more  or  less 
carmin.  Let  us  examine  such  a  cross-section  with  a  magni- 
fying power  of  1000  diameters  under  the  microscope. 

"  At  a  certain  distance  from  the  decay  the  canaliculi  look 
unchanged,  and  each  contains  the  central  transverse  section  of 
the  dentinal  fiber  with  its  delicate  radiated  offshoots.  (See  Fig. 
249.)  N'earer  to  the  decay  we  meet  with  moderately-enlarged 
canaliculi,  the  center  of  which  is  occupied  b}'  a  cluster  of  proto- 
plasm, the  granules  and  threads  of  which  have  readily  taken 
up  the  carmin.  One  step  farther  we  find  the  canaliculi  consid- 
erably enlarged,  to  double  or  treble  their  original  size,  and  filled 

33 


498 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


with  yellow  protoplasm,  plainly  exhibiting  the  net-like  arrange- 
ment of  the  living  matter.  The  most  peripheral  granules  send 
delicate  conical  otFshoots  through  the  surrounding  light  space 
toward  the  unchanged  basis-substance.  In  some  of  the  enlarged 
canaliculi  accumulations  of  living  matter  are  seen  fully  in  the 
shape  of  nuclei;  sometimes  two  or  more  such  nuclei  maybe 
seen  surrounded  by  a  varying  amount  of  protoplasm.  Still 
nearer  to  the  decay  the  canaliculi  are  enlarged  to  ten  or  fifteen 

Fig.  249. 


Caries  or  Destine. 

i^,  unchanged  dentinal  fiber;  P,  enlarged  dentinal  canaliculi,  filled  with  protoplasm;  H, 
medullary  corpuscles  in  considerably  widened  dentinal  spaces  ;  G,  complete  transformation  of 
dentine  into  medullary  corpuscles.    Magnified  1000  diameters. 


times  their  original  diameter,  and  the  cavities  thus  produced 
are  all  filled  with  a  partly-nucleated  protoplasm.  Between  the 
roundish  cavities  we  meet  with  longitudinal  cavities,  arising 
from  the  confluence  of  several  cavities  in  one  main  direction. 
The  cavities  continue  increasing  in  size,  and  form  large  spaces, 
with  rounded,  bay-like  boundaries,  between  which  only  scanty 
traces  of  unchanged  basis-substance  are  left.     Lastly,  the  basis- 


CARIES  OF  THE  TEETH.  499 

substance  lias  entirely  disappeared,  and  only  protoplasm  is  visible 
in  its  place,  either  in  the  shape  of  multinuclear  layers  or  of  ir- 
regular so-called  medullary  elements  with  rather  faint  marks  of 
division.  Nearest  to  the  periphery  the  protoplasm  does  not 
exhibit  any  form  elements,  but  looks  like  a  disintegrated  granu- 
lar mass,  probably  intermixed  vrith  or  replaced  by  micrococci. 
I  say  probably,  inasmuch  as  all  good  histologists  agree,  nowa- 
days, that  the  diagnosis  of  micrococci  is  possible  only  when  they 

Fig.  250. 


-.V 


Caries  or  Dextixe.    Oblique  Seciiox. 

P,  widened  dentinal  canaliculi,  containing  protoplasm ;  N,  space  eontaining  medullary  cor- 
puscles :  M,  transformation  of  dentine  into  protoplasm ;  0,  trace  of  dentinal  canaliculus  con- 
taining an  enlarged  fibril.    Magnified  1000  diameters. 

are  clustered  together,  which  is  not  always  demonstrable  even 
in  the  thoroughly-decayed  mass. 

''  We  have  a  series  of  changes  of  the  dentine  iibers,  and  the 
surrounding  basis-substance  of  the  dentine  before  us,  which  T 
have  not  the  least  doubt  is  the  normal  procedure  of  the  trans- 
formation of  dentine  by  the  carious  j^rocess. 

"  Fig.  250  is  an  oblique  section,  and  illustrates  exactly  the 
same  changes  from>  tooth  attacked  by  a  less  acute  caries,  per- 


500  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

haps  owing  to  its  greater  solidity  or  more  perfect  calcification. 
Here  a  relatively  small  nnniber  of  dentinal  canaliculi  are  en- 
larged and  filled  with  pratoplasm.  The  center  of  the  proto- 
plasmic bodies  is  occupied  by  one  or  two  nuclei,  which  look  as 
if  they  originated  from  the  former  dentinal  fiber.  On  the  per- 
iphery of  the  dentine  there  are  regular  nests  filled  with  proto- 
plasmic formations  of  the  above  description,  partly  broken 
down  into"  medullary  elements.  In  other  parts,  on  the  con- 
trary, the  transformation  of  the  basis-substance  into  protoplasm 
has  even  preceded  the  changes  of  the  dentinal  fibers.  The  cana- 
liculi are  not  noticeably  enlarged ;  the  dentinal  fibers  are  either 
unchanged  or  slightly  swollen,  and  more  granular  than  in  the 
normal  condition;  while  outside  these  we  have  a  thoroughly 
decalcified  and  liquefied  basis-substance,  which  means  a  reap- 
pearance of  the  net-work  of  the  living  matter. 

"  Caries  of  Cement. — So  long  as  the  gums  are  in  their  normal 
condition  and  position,  caries  does  not  begin  in  the  cement;  but 
if  the  gums  have  receded  from  any  cause,  thus  exposing  the 
cement  which  covers  the  necks  of  the  teeth,  it  may  then  begin 
to  decay.  I  never  have  had  an  opportunity  of  examining 
primary  caries  of  cement  under  the  microscope,  but  of  caries 
of  this  tissue  advanced  from  within — viz,  from  decayed  dentine 
— I  have  several  specimens.  The  microscope  reveals  in  these 
specimens  a  more  or  less  advanced  decay,  which  in  its  essential 
features  is  fully  analogous  to  caries  of  the  dentine  when  in  a 
live  condition;  in  other  words,  it  is  an  inflammatory  process. 
On  the  boundary  of  the  caries  we  see,  besides  unchanged  cement- 
corpuscles  (see  Fig.  251),  those  which  have  been  enlarged  and 
transformed  into  medullar}'  or  inflammatory  elements.  Nay,  I 
have  observed  that  the  lacun?e  holding  the  protoplasmic  body 
were  parth^  unchanged,  while  a  part  participated  in  the  inflam- 
matory process. 

"  The  enlargement  of  the  cement-corpuscles  is  evidently  not 
due  to  a  direct  swelling  of  the  ]>rotoplasm  itself,  but  to  a  lique- 
faction of  the  surrounding  basis-substance,  in  which  the  proto- 
plasmic condition,  and  with  this  also  the  medullary  elements 
which  have  participated  in  the  formation  of  the  basis-substance, 
reappear.  The  inflamed  portions  of  the  cement  look  granular 
with  lower  powers  of  the  microscope,  but  high  powers  reveal 
the  net-like  structure  of  the  living  matter,  and  the  formation  of 
irregular  polyhedral  elements  which  are  separated  from  one  an- 


CARIES    OF    THE    TEETH.  501 

other  by  a  light,  narrow  seam,  this  being  traversed  bv  extremely 
delicate  uniting  threads. 

"  The  history  of  development  of  bone  demonstrates  that  this 
tissue  originates  from  medullary  elements,  the  so-called  osteo- 
blasts, which  partly  remain  unchanged,  and  as  such  form  the 
bone-corpuscles,  while  their  greater  part  is  transformed  into 
basis-substance  (Waldeyer).  The  history  of  the  development 
of  the  cement  has  not  as  yet  been  studied,  but  we  have  good 
reasons  for  assuming  that  it  develops  in  a  way  identical  with 

Fig.  251. 


::a 


Cemextitis  due  to  Caries. 

C,  unchanged  cement-corpuscles ;  /,  space  filled  with  medullary  corpuscles ;  P,  cement-cor- 
puscles partly  unchanged,  partly  transformed  into  medullary  corpuscles;  M,  the  eementum 
wholly  transformed  into  medullary  corpuscles.    Magnified  1000  diameters. 

that  of  bone,  as  both  tissues  are  identical  in  their  structure,  and 
exhibit  identical  results  when  inflamed. 

"  Dr.  C.  Heitzmann  has  drawn  attention  to  the  fact  that  the 
protoplasm  of  the  medullary  elements,  when  transformed  into 
glue-yielding  basis-substance,  does  not  altogether  perish.  It  is 
only  the  fluid,  non-living  part  of  the  protoplasm  which,  by 
chemical  changes,  is  transformed  into  glue;  the  living  part  of 
the  protoplasm,  on  the   contrary,  remains   unchanged,  and  is 


502  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

simply  concealed  by  the  refracting  power  of  the  ^/ue-j/zeM??// basis- 
substance.  That  this  view  is  a  correct  one  the  investigator 
named  has  proven  by  the  appearances  in  inflamed  bone,  and  I 
can  fully  corroborate  his  views  from  my  observations  on  in- 
flamed cement. 

"  Virchow's  view  that  the  bone-corpuscles  swell  and  divide 
into  inflammatory  elements  by  being  converted  into  prolifer- 
ating mother-cells,  is,  in  my  opinion,  wrong.  No  proliferation 
is  demonstrable  in  the  earliest  stages  of  inflammation  of  the 
cement.  I^othing  but  a  liquefaction  of  the  glue-yielding  basis- 
substance  takes  place,  in  order  to  bring  to  view  the  very  same 
medullary  elements  which  once  have  shared  in  the  formation 
of  the  cement.  The  inflammatory  reaction  in  the  cement- 
corpuscle  itself  may  be  so  slight  that  (as  mentioned  above) 
a  part  of  the  protoplasm  may  look  almost  unchanged,  while 
another  part  toward  the  decalcified  basis-substance  gives  an 
appearance  identical  with  that  of  the  surrounding  liquefied 
basis-substance.  The  result  of  this  process  is  a  transformation 
of  the  tissue  of  the  cement  into  medullary  or  inflammatory 
elements.  These  remain  in  connection  with  one  another  by 
delicate  threads  of  living  matter,  but  at  last  become  disinte- 
grated, and  furnish,  together  with  micrococci  and  leptothrix 
threads,  a  decayed  mass,  just  as  well  as  enamel  and  dentine. 

"  JResults. — After  having  examined  the  teeth  attacked  by  the 
carious  process,  microscopically,  from  the  mouths  of  over  thirty 
diflferent  persons,  I  can  sum  up  the  results  of  my  researches  in 
the  following  aphorisms : 

"I.  In  enamel,  caries  in  its  earliest  stages  is  a  chemical  pro- 
cess. After  the  lime-salts  are  dissolved  through  the  inflamma- 
tory reaction,  and  the  basis-substance  liquefied,  the  protoplasm 
reappears  and  breaks  apart  into  small,  irregularly-shaped,  so- 
called  medullary  or  embryonal  bodies,  and  subsequently  the 
lime-salts  are  dissolved  by  acids  or  washed  away. 

"II.  Caries  of  dentine  consists  of  a  dissolution  of  the  lime- 
salts  in  the  intertubular  substance  by  the  inflammatory  reaction, 
a  melting  down  of  the  glue-yielding  basis-substance  (matrix) 
around  and  between  the  canaliculi.  The  living  matter  con- 
tained in  the  canaliculi  proper  is  transformed  into  nucleated 
protoplasmic  bodies,  which,  together  with  protoplasmic  bodies 
originating  from  the  living  matter  in  the  basis-substance,  form 
the  so-called  indiflerent  or  inflammatorv  tissue. 


CARIES    OF    THE    TEETH,  503 

"  III.  Caries  of  cement  exhibits  first  all  phenomena  known  to 
be  present  in  the  early  stages  of  inflammation  of  bone.  The 
protoplasmic  cement-corpnscles,  together  with  the  basis-sub- 
stance, after  its  liquefaction,  produce  indifferent  or  inflamma- 
tory elements. 

"  IV".  The  indifferent  elements  orighiating  through  the  carious 
process  from  enamel,  dentine,  and  cement  do  not  proceed  in 
new  formation  of  living  matter,  but  become  disintegratexl  and 
transformed  into  a  mass  crowded  with  micrococci  and  leptothrix. 

"V.  Caries  of  a  living  tooth,  therefore,  is  an  inflammatory 
process,  which,  beginning  as  a  chemical  process,  in  turn  reduces 
the  tissues  of  the  tooth  into  embryonic  or  medullary  elements, 
evidently  the  same  as  during  the  development  of  the  tooth  have 
shared  in  its  formation ;  and  its  development  and  intensity  are 
in  direct  proportion  to  the  amount  of  living  matter  which  they 
contain,  as  compared  with  other  tissues. 

"VI.  The  medullary  elements,  owing  to  want  of  nutrition 
and  to  continuous  irritation,  become  necrosed,  and  the  seat  of 
a  lively  new  growth  of  organisms  common  to  all  decomposing 
organic  material, 

"  Yll.  Micrococci  and  leptothrix  by  no  means  produce  caries ; 
they  do  not  penetrate  the  cavities  in  the  basis-substance  of  the 
tissues  of  the  tooth,  but  appear  only  as  secondary  formations, 
owing  to  the  decay  of  the  medullary  elements. 

"  VIII.  In  dead  and  artificial  teeth  caries  is  a  chemical  pro- 
cess, assisted  only  by  the  decomposition  of  the  glue-yielding 
basis-substance  of  dentine  and  cement." 

W,  D.  Miller's  Views,"^ — "  Physical  Phexomexa  of  Dental 
Decay, — a.  Decay  of  Enamel. — As  the  first  indication  that  the 
process  of  destruction  has  begun  on  the  external  surface  of  the 
enamel,  we  notice  that  it  has  lost  its  normal  polish  and  trans- 
parency;  then  a  white  (not  black)  spot  of  chalky  color  appears; 
a  sharp  instrument  {e.g.,  the  point  of  a  needle)  will  not  easily 
glide  over  the  surface,  but  will  readily  detect  the  presence  of  a 
slight  roughness,  caused  b}-  a  softening  or  disintegration  of  the 
enamel,  by  which  it  is  gradually  changed  into  a  soft,  cheesy 
powder.  This  dissolution  of  the  enamel  may  be  best  observed 
when  decay  advances  from  the  dentine  upon  the  inner  surface 

*  "  The  Micro-Orsanisms  of  the  Human  Mouth."'  1890. 


504  THE    ANATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

of  the  enamel  (secondary  decay);  here  the  broken-down  enamel- 
prisms  cannot  be  washed  away,  so  that  quite  a  thick  layer  of  a 
perfectly  white  cheesy  substance  may  often  be  found. 

"  In  primary  decay  the  disorganized  enamel-prisms  are  soon 
mechanically  washed  away,  whereby  an  excayation  or  cayity  is 
formed.  The  form  of  the  cayity  depends  upon  various  circum- 
stances,— among  others,  upon  the  breadth  of  surface  of  contact 
with  the  adjacent  tooth,  also  in  a  high  degree  upon  the  struc- 
ture of  the  enamel.  It  is  sometimes  flat  and  broad  with  scarcely 
distinguishable  margins,  sometimes  narrow  and  deep  with  sharp 
ragged  margins.  Soon  after  the  commencement  of  decay,  a 
more  or  less  pronounced  discoloration  sets  in.  In  my  opinion, 
the  view  held  by  some,  that  the  discoloration  is  to  be  regarded 
as  the  first  sign  of  decay,  is  based  on  an  error  which  is  to  be 
explained  only  on  supposition  that  the  advocates  of  this  view 
have  not  examined  decay  in  its  earliest  stages.  .  .  .  Dis- 
coloration appears  in  very  ditferent  grades :  when  the  decay 
proceeds  very  rapidly  (caries  acutissima),  it  is  slight  or  wholly 
wanting  (white  decay).  In  other  cases  only  the  margin  of  the 
enamel  is  colored  brown  to  black,  while  the  center  of  the 
cavity  remains  white.  When  the  decay  proceeds  very  slowly, 
— that  is,  when  it  is  of  long  standing  (caries  chronica), — the 
greater  part  of  the  affected  tissue  is  deep  brown  or  black. 
This  is  also  the  case  when  the  progress  of  the  decay  has  been 
interrupted,  as  is  often  observed  on  the  approximal  surfaces  of 
teeth  which  have  been  exposed  by  extraction  of  an  adjacent  tooth. 
Such  cases  are  usually  designated  as  caries  nigra  (black  decay). 
This  badly-chosen  term  must,  however,  not  mislead  us  to  sup- 
pose that  we  have  to  do  here  with  an  especial  form  of  decay. 
As  a  matter  of  fact,  we  are  scarcely  entitled  to  speak  of  such 
places  as  decay  at  all,  any  more  than  we  are  to  say  that  a  man 
with  a  pockmarked  face  has  got  the  smallpox,  because  they  do 
not  indicate  that  the  process  of  decay  is  going  on  at  the  time 
being.  They  are  simply  degenerated  tissue,  which,  in  the 
course  of  time,  has  become  discolored  b}^  oxidation,  precipita- 
tion, or  other  processes  of.  this  nature.  Decay-marks  would  be 
a  much  better  name  for  such  spots. 

"  b.  Decay  of  Dentine. — By  the  progress  of  the  above-described 
process,  the  destruction  of  the  enamel  spreads  until  the  surface  of 
the  dentine  is  reached.  Here  the  disease  takes  on  a  \qv\  differ- 
ent  form,  inasmuch   as    we    no  lono-er  find  the   tissue  being 


CARIES    OF    THE    TEETH.  505 

changed  into  a  soft,  cheesj  mass,  but  into  a  tough,  cartilaginous 
substance,  which  does  not  readily  fall  to  pieces  or  yield  to  the 
slightest  friction,  as  does  the  decayed  enamel,  but  may  retain  its 
form  for  some  time.  This  stage  is  designated  as  softening  of 
dentine,  and  is  conditioned,  as  will  be  seen  below,  by  a  more  or 
less  complete  decalcification  of  the  dentine.  This  softening 
spreads  in  all  directions  in  the  dentine,  with  a  rapidity  depend- 
ent upon  the  intensity  of  the  fermentation  processes  present  in 
the  mouth  and  the  physical  and  chemical  constitution  of  the 
dentine. 

"  The  softened  mass  may  be  easily  cut  or  peeled  off  with  a 
sharp  instrument ;  upon  pressure,  it  discharges  a  small  quantity 
of  a  liquid  which,  in  the  great  majority  of  cases,  will  be  found  to 
redden  blue  litmus  paper, — i.e.,  to  have  an  acid  reaction. 

"  The  thickness  of  the  softened  layer  varies  considerably  in 
different  cases.  Yery  soon  after  the  softening  of  the  dentine, 
its  disintegration  or  dissolution  begins,  leading  to  the  formation 
of  a  cavity  in  the  dentine.  The  surface  now  appears  uneven, 
soft,  and  porous,  infiltrated  and  contaminated  with  particles  of 
fermenting  food,  masses  of  bacteria,  etc. 

"  The  discoloration  of  the  dentine  is  brought  about  by  the 
same  causes  as  that  of  the  enamel;  it  also  shows  the  same 
variations  in  acute  and  chronic  decay,  and  all  shades  ft-om  the 
natural  color  of  dentine  to  black 

"  c.  Decay  of  Cement. — Decay  of  cement  frequently  occurs  at 
the  neck  of  the  tooth.  The  layer  of  cement  is,  however,  so  thin 
here  that  the  characteristic  phenomena  of  cement-caries  scarcely 
become  apparent.  Caries  of  the  cement  of  the  root  occurs  only 
when  the  latter  is  exposed,  and  is  therefore  comparatively  rare. 

"  The  roots  of  molars  which  are  laid  bare  by  the  recession  of 
the  gum  and  destruction  of  the  periosteum  show  the  greatest 
preference  for  decay.  Such  roots  are  often  covered  with  thick 
white  or  yellowish-white  deposits,  consisting  of  food-particles, 
dead  epithelium,  mucus,  and  fungus-masses,  and  not  infrequently 
present  cases  of  typical  decay  of  the  cement. 

"  The  first  symptom  of  cement-decay  is  an  abnormal  rough- 
ness or  softness  of  the  cement-surface,  which  may  be  easily 
penetrated  or  scraped  off  with  an  excavator. 

"  This  phenomenon,  which  is  also  nothing  but  the  softening 
of  the  cement,  is  followed  by  a  loss  of  the  surface  substance; 
thus  a  cavity  is  produced,  or  rather  a   depression,  since  it  has 


506  THE    ANATOMY    A'SB    PATHOLOGY    OF    THE    TEETH. 

little  similarity  with  the  cavities  of  the  crown.  Deep  bulb- 
shaped  cavities  are  hardly  ever  formed;  they  are,  for  the  most 
part,  shallow,  widely-extended  excavations,  without  a  distinct 
margin. 

"  This  is  due  to  the  fact  that  there  are  no  circumscribed 
points  of  retention  or  foci  of  decay  on  the  roots,  from  which 
alone  the  destruction  could  proceed.  It  therefore  seldom 
happens  that  decay,  beginning  at  the  root,  spreads  from  the 
cement  to  the  dentine,  and  destroys  the  latter  to  such  an  extent 
that  the  root-pulp  is  exposed. 

"  A  natural  retention-center  is  formed  at  the  point  of  bifur- 
cation of  the  molar  roots,  where  it  has  been  exposed  by  recession 
of  the  gums,  and  penetrating  decay  is  consequently  not  seldom 
found  here.     .     . 

"  Aecompaivjing  Phenomena  of  Dental  Decay. — As  concomitant 
phenomena  of  dental  decay,  I  designate  certain  processes  which 
manifest  themselves  either  immediately  or  some  time  after  the 
appearance  of  decay,  and  which,  in  my  opinion,  have  been 
erroneously  denominated  as  characteristics  of  it. 

"These  processes  are:  (1)  transparency;  (2)  the  pigmenta- 
tion or  discoloration  of  the  decayed  tissue. 

"  Coincident  with  the  development  of  the  opacity  and  the 
pigmental  degeneration  in  the  commencement  of  the  carious 
affection  of  the  dentine,  an  increased  translucency  is  observed^ 
frequently,  in  portions  adjacent  to  the  boundary  of  the  carious 
portion.  With  reflected  light  these  portions  have  a  horny 
appearance,  similar  to  that  found  in  senile  roots,  and  ^vith 
transmitted  light  they  present  liyaline  bands  and  spots.  The 
focus  of  the  caries  is  surrounded  by  a  diaphanous  halo.  The 
opaque,  carious  dental  cone,  therefore,  is  invested  by  a  trans- 
lucent zone,  extending  from  the  periphery  toward  the  center ; 
around  a  more  spherical,  carious  pox'tion  of  the  dentine  a  cres- 
centic  diaphanous  halo  is  sometimes  met  with.  (Fig.  252.)  The 
light  portions,  finally,  vary  exceedingly  in  respect  to  their  out- 
lines, according  to  the  form  in  which  the  carious  limits  are 
extended,  being  radiated,  kidney-shaped,  etc.  (Wedl.) 

"  A  true  picture  of  transparency  can  be  obtained  only  where 
softening  and  pigmentation  of  the  dentine  have  not  yet  taken 
place  ;  that  is  to  say,  where  there  is  as  yet  no  decay. 

"  The  transparent  portion  here  forms  a  cone  whose  apex 
points  toward  the  pulp,  and  whose  sides  run  parallel  with  the 


CARIES    OF    THE    TEETH. 


507 


dentinal  tubules.  In  most  cases  the  transverse  sections  of  these 
cones  are,  as  far  as  my  observations  go,  bounded  by  two  opaque 
stripes. 

"  Under  the  microscope  the  dentinal  tubules  within  these 
stripes  are  seen  to  be  filled  with  irregular,  angular  granules  or 
oblong  particles. 


Portion  of  a  Longitudinal  Ground  Section  through  the  Crown  of  a  Molar. 
Showing  two  cavities  of  decay,  with  the  transparent  zone  at  c.    (After  Gysi.) 


"  Pigmentation  of  the  Tissue  in  Dental  Decay. — The  pigmen- 
tation or  discoloralion  usually  attending  decay  of  enamel  or 
dentine  is  another  secondary  process,  which  has  erroneously  been 
viewed  as  a  stage  of  decay.  Every  degree  of  discoloration  may 
be  observed,  from  the  normal  color  of  the  tissue  to  a  yellow- 


508  THE    AXATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

isli,  yellow,  j-ellowisli-brown,  dark  brown,  black.  In  the  very 
first  appearance  of  decay  no  discoloration  is  visible.  This  ab- 
sence of  discoloration  is  especially  remarkable  in  secondary  caries 
of  enamel,  the  tissue  being  converted  into  a  perfectly  white 
powder. 

"  Nor  does  rapid  caries  show  any,  or  but  very  little,  discolora- 
tion in  the  deeper  parts,  while  chronic  caries  always  exhibits  a 
dark  color,  dark  brown  to  black  ;  in  other  words,  the  intensity  of 
the  discoloration  is  in  inverse  proportion  to  the  rapidity  of  the 
progress  of  the  disease.  Besides,  the  discoloration  of  dentine 
does  by  no  means  occur  in  decay  only.  Wherever  the  dentine  is 
laid  bare, it  maybe  more  or  less  discolored  in  time.  The  black 
discoloration  is  especially  common  in  worn-off  teeth,  and,  in- 
deed, not  only  in  the  case  of  smokers,  but  also  of  non-smokers, 
nor  is  it  rare  for  the  teeth  of  dogs  to  show  a  deep  brown  to 
black  discoloration. 

"  Most  authors  concur  in  the  view  that  the  pigment  arises 
from  without,  and  is  conditioned  by  causes  which  have  nothing 
to  do  with  the  deca}^  itself 

"  In  my  judgment,  the  cause  of  discoloration  in  dental  caries 
is  exactly  the  same  as  that  of  the  discoloration  of  any  other 
organic  substance  which  is  decomposed  by  micro-organisms. 

^^  Decay  of  Enamel. — Microscopic  examination  of  decayed 
enamel  brings  to  light  in  many  preparations  nothing  more  than 
a  depression  (a  loss  of  substance),  with  uneven  margins  (Fig. 
253),  a  more  or  less  pronounced  pigmentation  of  the  enamel  in 
the  vicinity  of  the  depression,  and  a  distinct  appearance  of  the 
transverse  striation  of  the  enamel-prisms.  In  other  better-pre- 
pared specimens  the  depression  is  seen  to  be  filled  with  masses 
of  micro-organisms  which  readily  take  on  coloring  matter;  the 
margin  of  the  cavity  is  indented,  the  enamel  cracked,  the 
prisms  falling  to  pieces.  The  spaces  between  the  loosened 
prisms  are,  in  these  cases,  often  filled  with  the  same  fungal 
masses,  whereas  the  latter  never  penetrate  between  the  prisms 
of  normal  enamel.  In  grinding,  the  masses  of  bacteria,  as  well 
as  the  loosened  prisms,  are  generally  torn  away. 

"  After  the  enamel  has  once  been  perforated  by  decay,  its 
further  destruction  proceeds  principally  from  the  inner  surface. 
This  statement  may  at  first  seem  strange,  but  will  be  found  on 
closer  examination  to  be  in  accordance  with  the  observed  facts. 
The  remains  of  food  accumulating  in  every  dental  cavity  do 


CARIES    OJb'    THE    TEETH. 


509 


not,  of  course,  attack  the  external,  hut  the  internal  surface  of 
the  enamel.  We  will  find,  furthermore,  in  nearly  all  large 
cavities  the  decay  extending  from  the  dentine  upon  the  inner 
surface  of  the  enamel. 

"  This  latter  form  of  decay,  which  we  designate  as  secondary 
enamel-decay,  is  in  many  respects  better  suited  for  study  than 
the  primary,  inasmuch  as  the  diseased  tissue  is  not  torn  away 

Fig.  253. 


Under  MIXING  E.vamel-Decay. 
a,  masses  of  bacteria  lining  the  cavity.    Magnified  about  50  diameters. 


by  mastication,  etc.,  and  not  contaminated  from  without  by 
foreign  bodies. 

"  Sections  of  enamel  in  secondary  decay  often  show  the  bac- 
teria forcing  their  way  between  the  loosened  prisms.  About 
the  same  result  is  obtained  where  normal  enamel  is  treated 
with  diluted  acids.  The  destruction  of  the  enamel  as  it  occurs 
in  decay  must  be  regarded  as  essentially  a  parasitico-chemical 
process.  The  loosening  of  the  enamel-prisms  is  caused  by  acids, 
concerning  whose  origin  there  can  be  no  doubt ;  they  arise  in 


510  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

the  mouth  by  fermentatiou  of  carbohydrates.  The  prisms  thus 
loosened  are  sometimes  mechanically  removed;  sometimes  they 
remain  on  the  spot,  as  in  the  case  of  secondary  enamel-decay, 
until  an  opening  is  formed  through  which  they  escape.  The 
bacteria  directly  participate  in  the  process,  inasmuch  as  they  in- 
vade the  broken-down  enamel,  perhaps  drive  the  prisms  farther 
apart,  and  destroy  the  remnant  of  organic  matter.  Micro-organ- 
isms do  not  exert  a  direct  influence  on  normal  enamel;  their 
action  upon  the  enamel  in  the  first  stage  of  decay  is  therefore 
indirect, — that  is,  they  act  by  means  of  the  acids  which  they  pro- 
duce. In  the  later  stages  of  the  process  they  exert  also  a  direct 
action  upon  the  diseased  tissue. 

'■'■Decay    of   Dentine. — Airpearances    under    the    Microscope. — 
Preparations  colored  with  fuchsin,  when  examined  under  very 

Fig.  254. 


IXTEEGLOBULAR    SPACES   FILLED   '^ITH   MiCEOCOCCL.;. 

Magnified  about  400  diameters. 

low  power  or  even  with  the  naked  eye,  show  that  the  bacteria 
are  not  equally  distributed  throughout  the  mass  of  softened 
dentine.  Sections  parallel  to  the  dentinal  tubules  (longitudinal 
sections)  generally  reveal  on  the  outer  margin  corresponding 
to  the  external  layer  of  dentine  a  deep-red  coloration,  which 
gradually  diminishes  toward  the  inner  margin.  Large  tracts  of 
decayed  tissue,  especially  at  the  extremities  of  the  specimen, 
often  remain  entirely  uncolored.  This  necessitates  the  conclu- 
sion that  the  softening  (decalcification)  of  the  dentine  extends 
further  than  the  invasion  of  the  micro-organisms. 

"  Under  a  somewhat  higher  power  (forty  to  sixty  diameters) 
we  may  more  easily  follow  the  invasion.  Occasionally  we  find 
that  a  majority  of  the  tubules  are  infiltrated  to  the  same  depth; 


CARIES    OF    THE    TEETH. 


511 


usually,  however,  the  parasites  penetrate  the  diiierent  tubules 
to  very  different  depths.  We  also  occasionally  find  that  all  or 
nearly  all  the  tubules  are  filled  with  bacteria  at  the  surface, 
while  in  the  deeper  parts  only  a  few  are  infiltrated. 

"A  question  which  has  often  been  mooted  now  arises :  Can 
the  bacteria  penetrate  into  normal  dentine  ?  This  question  must 
be  answered  in  the  aflSrmative.  Since  the  average  diameter  of 
the  dentinal  tubules  is  greater  than  that  of  the  bacteria  found 
in  the  mouth,  it  is  but  reasonable  to  conclude,  a  priori,  that  bac- 

FiG.   255. 


Lecayed  Dextixe. 
ShowiDg  total  liquefaction  of  the  basis-substance  by  bacteria.    Magnified  400  diameters 


teria  may  under  certain  circumstances  make  their  way  into  the 
tubules  of  apparently  intact  tissue.  Under  high  power  we  also 
often  observe  that  a  small  number  of  bacteria,  outposts,  as  it 
were,  have  penetrated  into  the  normal  dentine,  without,  how- 
ever, producing  any  visible  changes. 

"  In  some  specimens  all  the  tubules  are  enlarged  to  nearly  the 
same  extent,  occasionally  to  three  or  four  times  their  normal 
size.     This   enlargement  is  caused  partly  by  the  dislodgment 


512 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


of  the  neighboring  tubules,  partly  by  the  loss  of  the  inter- 
tubular  substance.  Lastly,  the  destruction  of  the  intervening 
substance  causes  a  confluence  of  two  or  more  adjacent  tubules, 
producing  long  caverns  running  parallel  to  them.  By  the  form  a- 
tion  of  caverns  and  by  the  fusion  of  adjacent  caverns  the  dentine 
is  broken  up,  becomes  porous,  and  is  gradually  destroyed. 
The  tubules  are  often  attacked  in  groups,  while  others  lying  be- 
tween these  groups  may  be  wholly  free  from  infection.  In  other 
cases,  however,  every  single  canal  is  stufied  full  of  bacteria. 
"  In  Fig.  255  I  have  endeavored  to  reproduce  an  appearance 


Fig,  256. 


Fig.  2b'i 


Fig.  258. 


Fig.  259. 


Fig.  260. 


Single  Tubule.    Single  Tubule.  Single  Tubule.  Single  Tubule 


Filled  with  thread  Filled  with  Filled  with 
forms.  Magnified  eocci.  Magnified  rods.  Magnified 
1100  diameters.  1100  diameters.        1100  diameters. 


Showing  a  mix- 
infection  or  infct  - 
tion  with  a  pko 
morphous  b  a  c 
terium.  Magnified 
1100  diameters. 


A-^ 


verv  commoulv  met  with  in  decavino:  dentine.  Thi- 
specimen  clearly  shows  that  the  enlargement  of  the 
tubules  always  found  in  decaj'ed  dentine  is  due  to 
the  infection,  and  that  a  gradual  fusion  of  the  basis- 
substance  may  take  place,beginuing  with  the  sepa- 
rate tubules,  until  nothing  remains  but  a  maps  of 
bacteria  held  together  by  the  remnants  of  the 
dentine. 

"  In  well-stained  specimens  the  individual  cells 
teria  are  clearly  ^^sible  under  a  power  of  400  to  500 
although  for  a  thorough  study  of  the  specimens  oil 


f   I   \ 


Decayed  Den- 
tine. 

Showing  a  mix- 
infection  with 
cocci  and  ba- 
cilli. Magnified 
400  diameters. 

of  the  bac- 
diameters; 
immersion 


CARIES  OF  THE  TEETH.  513 

lenses  and  Abbe's  condenser  are  desirable.  "With  tlieir  assist- 
ance we  see  that  the  external  margin  of  the  specimen  consists 
of  broken-down  dental  tissne  intermixed  with  enormous  masses 
of  micrococci,  bacilli,  and  leptothrix  threads.  The  latter  often 
appear  as  fringes  on  the  border  of  the  specimen,  but  are  not 
found  along  the  entire  margin,  while  in  some  the\'  are  altogether 
lacking.  In  many  cases,  no  doubt,  they  are  torn  away  in  pre- 
paring the  specimens.  It  is  seldom  that  they  penetrate  the  den- 
tinal tubules,  unless  the  dissolution  is  already  far  advanced,  and 
even  then  they  are  to  be  found  mostly  in  the  external  layers. 
Tubules  containing  long,  tortuous  threads  (Fig.  256)  are  there- 
fore comparatively  rare. 

"  If  we  examine  a  somewhat  deeper  zone,  we  usually  hnd 
the  tubules  filled  with  micrococci  and  rods  only,  the  former 

Pig.  261. 


f^M 


e^hfe^^* 


Cross-Sectiox  of  Decayed  Dentine. 

Showing  the  distention  of  the  tubuli  and   formation  of  liquefaction-foci.     Magnified  400 
diameters. 

decidedly  preponderating.  These  two  forms  of  bacteria  gen- 
erally occur  in  separate  tubules;  thus  we  often  see  a  tubule 
stocked  only  with  micrococci  (Fig.  257),  the  adjacent  one  only 
with  rods  (Fig.  258),  while  it  rarely  happens  that  one  extremity 
of  a  tubule  is  filled  with  rods,  the  other  with  cocci. 

"  We  have  consequently  in  decay  of  the  teeth  to  do  with  a 
so-called  mix-infection  (Figs.  259  and  260). 

"It  is  true  that  we  often  meet  with  specimens  which  appear 
to  contain  cocci  alone  (whether  of  one  or  of  different  varieties 
the  microscopic  examination  does  not  tell).  On  the  other  hand, 
I  have  in  my  possession  a  few  preparations  which  exhibit  a  pure 
bacillus  infection,  particularly  in  circumscribed  portions. 

"A  section  cutting  the  tubules  at  right  angles  shows,  under  a 
power  of  300  diameters,  that  the  tubules  filled  with  micro-organ- 

34 


514  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH, 

isms  are  distended  from  one  to  four  times  their  normal  diameter, 
and  that  often  tTro  or  more  of  the  enlarged  tubules  are  converted 
into  one  by  the  liquefaction  of  the  membranes  and  the  interven- 
ing substance  (Fig.  261).  This  melting  together  of  the  tubules 
increases  as  we  near  the  outer  border  of  the  specimen  (corre- 
sponding to  the  surface  of  the  cavity),  until  it  is  no  longer  pos- 
sible to  distinguish  the  separate  tubules ;  v^e  then  see  only 
irregular  masses  of  bacteria,  of  different  sizes,  which  are  more 
or  less  contaminated  by  the  detritus  [debris)  of  the  decomposing 
dentine.  These  impure  masses  are  what  Abbott  calls  '  embry- 
onic elements.'  Since  they  are  not  homogeneous  they  take  up 
the  coloring-matter  unequally  at  different  points,  and  therefore 
occasionally  present  figures  that  may  bear  a  certain  faint  resem- 
blance to  cells. 

'■'•Decay  of  Cement. — The  decalcification  and  dissolution  of  the 
cement  proceeds  either  from  the  surface  inward,  in  the  form  of 
a  progressive  superficial  dissolution  of  the  cement,  or  the  cavi- 
ties of  the  cement  become  infiltrated  with  bacteria,  giving  rise 
to  a  parenchymatous  dissolution,  accompanied  by  phenomena 
very  similar  to  those  of  dentine-decay.  Its  similarity  to  the 
latter  is  especially  striking  in  places  where  Sharpey's  fibers  are 
well  developed.  Immediately  following  decalcification  these 
fibers,  or  rather  canals,  are  infiltrated  and  enlarged  by  bacteria 
which  gradually  liquefy  the  intervening  tissue.  In  this  way  the 
tissue  is  rarefied,  and  finally  totally  destroyed.  I  possess  several 
specimens  in  which  this  form  of  cement-caries  has  been  arti- 
.ficialh"  produced. 

"  Wlien  cement-corpuscles  are  present,  they  or  their  offshoots 
(as  far  as  I  have  had  opportunity  to  examine  such  cases)  are 
infiltrated  with  bacteria  and  swollen.  I  was  not  able  to  deter- 
mine any  such  inflammatory  reaction  on  the  part  of  the  cement 
as  occurs,  say  in  bone  or  cartilage. 

"I  atfirm  that  a  destruction  of  the  tooth-substance  maybe 
brought  about  artificially,  which  the  most  practiced  micro- 
scopist  will  not  be  able  to  distinguish  from  real  decay  as  it 
occurs  in  the  human  mouth.  In  fact,  not  one  of  the  many 
microscopists  who  have  made  the  attempt  has  been  able  to 
determine  which  of  a  given  number  of  preparations  were  arti- 
ficial and  which  natural. 

"  I  cut  up  a  number  of  teeth  which  were  perfectly  sound,  but 
of  different  density,  into  pieces  of  different  size,  and  placed 


CARIES  OF  THE  TEETH.  515 

them  in  a  mixture  of  saliva  and  bread.  This  mixture  was  for 
three  months  at  a  temperature  of  37°  C,  and  during  the  course 
of  the  experiment  repeatedly  renewed.  At  the  end  of  this 
time  I  showed  a  number  of  these  pieces  to  a  well-known  dentist 
of  thirty-three  years'  standing,  and  asked  him  if  these  were  not 
peculiar  cases  of  decay.  He  replied  by  saying  that  he  saw 
such  cases  every  day  in  his  practice.  In  many  pieces  the  den- 
tine was  softened  through  and  through,  in  all  to  a  considerable 
depth.  When  the  softening  had  penetrated  through  the  den- 
tine to  the  inner  surface  of  the  enamel,  the  latter  was  found 
covered  with  a  layer  of  white  powder  exactly  as  it  is  found  in 
natural  decay.  Cracks  and  fissures  in  the  enamel  had  an 
opaque,  whitish  appearance,  and  in  many  cases  could  be  easily 
penetrated  by  a  sharp  instrument.  At  the  neck  of  the  tooth 
the  dentine  was  likewise  much  softened,  though  not  to  so  great 
a  degree  as  on  the  crown.  The  border  of  the  enamel  was  rough, 
and  so  brittle  that  in  many  places  an  instrument  could  be 
inserted  between  the  enamel  and  the  dentine.  On  the  oTiadinof- 
surface,  in  such  cases  where  the  structure  of  the  tooth  was 
imperfect  and  full  of  fissures  or  depressions,  the  whole  tissue 
had  been  converted  into  a  soft  mass,  such  as  is  often  found  on 
the  surface  of  third  molars. 

"  All  of  the  phenomena  observed  in  cases  of  so-called  white 
decay  were  present  in  these  cases  of  artificial  decay.  If  the 
mixture  was  allowed  to  stand  until  the  reaction  became  alkaline, 
or  if  the  pieces  were  exposed  to  the  air  or  to  the  action  of  dif- 
ferent articles  of  food,  such  as  cofifee,  tea,  tobacco,  fruit,  etc., 
all  possible  shades  of  color  were  produced  just  as  they  are  found 
in  the  mouth. 

"  Sections  of  these  pieces  showed  all  the  microscopic  changes 
which  have  been  described  as  characteristic  of  decay  of  dentine. 

"  The  Micro- Organisms  of  Derital  Decay. — Our  knowledge  of 
the  micro-organisms  most  directly  concerned  in  the  destruction 
of  the  substance  of  the  tooth  is  as  yet  very  deficient.  We  have 
been  able  to  establish  the  fact  that  all  micro-organisms  of  the 
human  mouth  which  possess  the  power  of  exciting  an  acid 
fermentation  of  foods  may  and  do  take  part  in  producing  the 
first  stage  of  caries;  also,  that  all  possessing  a  peptonizing  or 
digestive  action  upon  albuminous  substances  may  take  part  in 
the  second  stage ;  and,  finally,  that  those  possessing  both  prop- 
erties at  the  same  time  may  take  part  in  the  production  of  both 


516  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

stages.  But  whether  there  is  any  one  bacterium  which  may 
alicays  be  found  in  decayed  dentine,  and  which  might  therefore 
be  entitled  to  the  name  of  the  bacterium  of  tooth-decay,  or 
whether  there  are  various  kinds  which  occur  with  considerable 
constancy,  we  are  not  able  to  say." 

From  the  quotations  of  Abbott  and  Miller  it  follows  that  the 
former,  although  he  noticed  the  micro-organisms  in  decayed 
teeth,  does  not  consider  them  the  primary  cause  thereof. 
Abbott,  however,  has  accurately  observed  the  tissue- changes  in 
the  neighborhood  of  decay  in  the  enamel,  dentine,  and  cemen- 
tum.  Miller,  on  the  contrary,  proved  that  the  invasion  of 
micro-oro-anisms  is  the  onlv  cause  of  decay;  but  admits  no 
inflammatory  reaction  whatsoever  in  the  affected  hard  tissue  of 
the  tooth.  In  the  views  of  the  latter  observer,  the  living  tissues 
are  simply,  destroyed  by  the  micro-organisms  without  reacting 
upon  the  injury. 

From  my  own  researches,  I  am  convinced  that  the  full  truth 
in  regard  to  the  carious  process  can  be  established  only  by  a 
combination  of  both  Abbott's  and  Miller's  assertions.  I  admit 
that  micro-organisms  are  the  principal  cause  of  the  decay  of 
teeth ;  but  onl}^  dead  material  will  be  destroyed  by  them  with- 
out the  least  reaction.  Living  tissues — i.e.,  enamel,  dentine, 
and  cementum — invariably  react  upon  the  invasion  of  the  micro- 
organisms by  an  inflammatory  process  similar  to  that  in  other 
li^nng  tissues,  in  the  manner  described  by  Abbott. 

The  brown  discoloration  of  the  dentine  in  the  neighborhood 
of  decay,  of  which  both  authors  speak,  affords  an  excellent  op- 
portunity for  studying  the  minute  structure,  especially  in  freshly- 
ground  specimens.  The  reticulum,  as  I  have  described  it  in 
Chapter  VIII,  is  seen  here  even  with  medium  powers  of  the 
microscope.  Pigmentation  of  enamel  in  the  neighborhood  of 
decay  likewise  furnishes  excellent  means  for  studying  its  minute 
structure  with  high  powers  of  the  microscope. 

Another  proof  of  the  tissue-changes  in  the  dentine  in  the 
vicinity  of  decay  is  the  healing  process  occasionally  observed. 
(See  Fig.  262.)  Here  a  recalcitication  of  the  softened  and  prob- 
ably inflamed  dentine  has  taken  place,  with  a  new  formation 
of  scanty  and  irregular  canaliculi,  such  as  we  frequently  observe 
in  secondary  dentine.  Since  all  modern  researches  in  biology 
prove  that  no  new  tissue  can  arise  without  the  previous  one  be- 


CARIES    OF    THE    TEETH.    .  517 

ing  first  reduced  into  an  embryonal  condition,  I  do  not  hesitate 
to  maintain  such  changes  for  the  living  dentine.  The  difference 
between  the  normal  and  the  newlj-formed  dentine  is  so  con- 
spicuous, especially  in  the  rearrangement  of  the  dentinal  caiiali- 
culi,  that  a  mere  recalcification  could  never  explain  these 
changes. 

According  to  the  views  thus  far  explained,  I  will  indicate  the 
changes  that  occur  in  the  process  of  caries  by  the  following : 

The  primary  cause  of  caries  is  acid  fermentation  of  remnants 


l^**x^ 


Fig.  262. 


0  =e 


Healed  Caries  of  Dextixe. 

i,  colonies  of  leptothrix  ;  D,  D,  decalcified  dentine,  with  enlarged  canaliculi ;  R,  B,  recalci- 
fied  dentine,  with  scanty  canaliculi;  N,  normal  dentine.    Magnified  500  diameters. 

of  food,  induced  by  micro-organisms.  The  favorable  starting- 
places  of  caries  in  the  enamel  are  grooves,  pits,  and  crevices  in 
the  surfaces  of  the  teeth,  where  particles  of  food  are  most 
readily  detained.  The  further  progress  of  caries  is  due  to  an 
invasion  of  micro-organisms  into  the  hard  tissues  of  the  teeth. 
The  result  of  this  invasion  is  first  decalcification  and  afterward 
disintegration.  Dead  tissues  are  decomposed  without  reaction. 
Living  tissues,  after  decalcification,  are  reduced  to  an  embry- 


518  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

onal  or  protoplasmic  condition  (Abbott).  According  to  the 
amount  of  lime-salts  therefor,  the  constitution  of  the  individual, 
and  according  to  the  number  of  micro-organisms  invading  the 
tissues,  the  decay  is  either  rapid  (acute  caries)  or  slow  (chronic 
caries).  In  the  latter  instance  a  spontaneous  healing  by  a 
re-formation  of  the  hard  tissues  is  possible.  In  dentine  and 
cementum  acute  caries  leads  to  a  white  discoloration  of  the 
tissues  involved,  Avhile  chronic  caries  frequently  causes  a 
brown  pigmentation  in  the  neighborhood  of  decay. 


CHAPTER   XLI. 


THE  EFFECTS  OF  ARSENIC  DIOXIDE  AND  METALLIC  ARSENIC  UPON  THE 
PULPS  :0F  THE  TEETH.-SO-GALLED  COAGULATION-NECROSIS. 

In  1884  I  published*  a  brief  account  of  experiments  with 
arsenic  dioxide,  of  which  the  following  is  an  abstract : 

The  action  of  arsenic  dioxide  upon  the  dental  tissues  has  for  a 
long  time  been  a  disputed  question,  and  the  changes  efiected  by 
the  poison,  when  applied  to  the  cavity  of  a  tooth,  were  thought 
to  be  confined  to  the  pulp-tissue.  In  1879,  A.  "Witzel,  of  Ger- 
many, published  a  work  on  the  diseases  of  the  dental  pulp.  In 
this  he  claims  that  a  pulp,  if  not  too  much  inflamed,  can  be 
treated  with  arsenic  dioxide,  its  coronal  portion  amputated,  and 
the  remaining  pulp-stump  preserved.  This  doctrine  has 
created  a  great  deal  of  controversy  in  this  country,  although  in 
Germany  it  seems  to  have  been  almost  universally  accepted. 
I  have  followed  this  line  of  treatment  in  sixteen  cases,  in  an 
.  experimental  way,  selecting  teeth  which  I  was  able  to  examine 
from  time  to  time.  The  microscopical  appearances  can  best  be 
studied  in  healthy  or  superficially  decayed  teeth  of  human  sub- 
jects, or  in  the  teeth  of  such  animals  as  can  be  easily  experi- 
mented upon.  In  ail  cases,  therefore,  a  uniform  mode  of  pro- 
cedure must  be  adhered  to.  The  line  of  study  being  neces- 
sarily experimental,  has  extended  over  a  long  period  of  time, 
calling  for  a  considerable  amount  of  labor  and  painstaking  care. 

*  Dental  Cosmos,  1884. 


EFFECTS    OF    AKSENIC    UPON    TOOTH-PULPS.  519 

The  preparation  which  I  have  used  exclusively  is  the  well- 
known  one  composed  of  one  part  of  arsenic  dioxide  and  one 
part  of  sulphate  of  morphia,  made  into  a  paste  with  chemically- 
pure  carbolic  acid,  which  was  put  into  a  drill-hole  in  the  tooth 
and  covered  with  a  temporary  stopping.  I.  will  not  enter  into 
details,  but  will  only  mention  that,  bearing  in  mind  the  results 
I  wished  to  obtain,  I  drilled  in  the  direction  of  the  pulp- 
chamber,  but  did  not  in  any  case  perforate  it.  It  appeared  to 
be  quite  immaterial,  however,  how  thick  the  interposing  den- 
tine was  in  respect  to  the  changes  caused  by  the  poison. 

I  used  human  teeth  and  those  of  rabbits.  They  were 
extracted  in  from  three  to  six  days  after  the  application  of 
arsenic  dioxide.  The  teeth  were  opened  immediately  after 
extraction,  and  immersed  without  delay  in  the  proper  reagent. 
It  is  important  to  proceed  in  such  manner  that  the  pulp  shall 
not  be  torn  or  dislodged,  and  yet  may  be  acted  upon  by  the 
fluids  while  still  lodged  in  its  natural  position.  "When  the 
elements  of  the  pulp  are  once  sufficiently  fixed,  it  becomes  pos- 
sible to  slice  it  without  causing  artificial  changes.  This  is  no 
easy  matter,  for  unluckily  the  hardening  fluids  most  generally 
in  use  cause  some  changes.  Even  water,  and,  as  has  been 
found,  the  tissue-fluid  itself,  if  allowed  to  act  a  sufficient  time 
after  death,  gives  to  the  medullated  nerve-fibers  an  appearance 
which,  I  have  no  doubt,  has  frequently  been  described  as 
pathological. 

After  having  used  dififerent  reagents,  I  have  come  to  the  con- 
clusion that  the  best  results  can  be  obtained  by  immersing  the 
tooth  in  the  manner  described  in  a  one  per  cent,  solution  of 
hyperosmic  acid  for  from  ten  to  twenty  hours,  according  to  the 
density  of  the  tooth.  As  regards  the  pulp,  this  will  be  found 
to  be  sufficiently  hardened  after  a  sojourn  of  two  to  three  hours 
in  the  same  fluid ;  it  can  then  be  easily  removed  from  the  pulp- 
chamber  without  fear  of  serious  harm.  Both  parts  are  then 
placed  in  distilled  water  and  preserved  in  alcohol. 

The  changes  due  to  the  poison  are  quite  pronounced.  First, 
if  the  poison  has  acted  sufficiently  long,  the  whole  of  the  pulp 
shows  to  the  naked  eye,  as  soon  as  exposed,  all  the  signs  of 
active  inflammation.  According  to  the  degree  of  inflammation 
resultant  from  the  irritation  which  the  arsenic  dioxide  undoubt- 
edly does  produce,  a  greater  or  less  number  of  nerve-fibers 
are  changed  in  appearance  in  such  a  manner  that  their  myelin 


520  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

is  separated  into  larger  and  smaller  masses,  between  which  I 
have  not  been  able  to  distinguish  either  an  axis-cylinder  or  an 
intermediate  substance.  I  may,  however,  mention  that  I  have 
seen  in  nerve-fibers,  which  have  remained  under  the  influence 
of  the  arsenic  dioxide  for  six  days,  a  granular  substance  which 
can  be  colored  by  rose  anilin,  certainly  a  product  of  the  disin- 
tegration of  the  myelin  sheath.  I  have  no  doubt  that  this  is  a 
stage  toward  the  complete  destruction  of  the  nerve-fibers,  and  I 
may  mention  in  this  connection  that,  in  one  instance,  I  have 
found  similar  globules  free  in  the  tissue  surrounding  a  number 
of  degenerated  nerve-fibers  in  an  incisor  of  a  rabbit  after  three 
days'  reaction  of  the  arsenic  dioxide. 

What  will  be  the  result  of  the  arsenic  dioxide  so  applied,  not 
alone  to  the  pulp  itself,  but  in  respect  to  the  nutrition  and  life 
of  the  whole  tooth,  is  easily  surmised,  and  can  be  demonstrated 
by  an  examination  of  the  dentine. 

After  ha\dng  treated  the  newly-extracted  tooth  with  hj-per- 
osmic  acid,  and  thereby  guarded  against  artificial  changes,  I 
prepared  ground  specimens  of  the  same.  These  were  then 
stained  with  picrocarmin,  and  suitably  treated  for  mounting. 
Under  the  microscope  the  dentinal  canaliculi  appear  enlarged, 
more  so  at  one  place  than  at  another,  and  filled  with  a  mass 
deeply  stained  in  black.  The  same  can  be  said  of  the  transverse 
connections  of  the  canaliculi.  When,  however,  high  powers 
are  brought  to  bear  on  such  places,  the  black  mass  is  found  to 
be  composed  of  irregularly-shaped  bodies,  which,  I  doubt  not, 
are  remnants  of  the  dentinal  fiber.  In  tracing  such  canaliculi, 
it  is  seen  that  the  swollen  dentine-fibers  are  broken  up  more 
and  more  as  one  approaches  the  seat  of  the  greatest  destruction. 
As  a  consequence,  the  basis-substance  is  narrowed  in  extent  as 
the  canaliculi  gain  in  diameter. 

Since  this  publication  I  have  continued  my  researches  on  the 
action  of  arsenic  dioxide,  examining  the  pulps  after  exposure  to 
the  poison  for  a  time  varying  from  twenty  minutes  to  twenty- 
four  hours.  The  pulps  were  obtained  either  after  the  extrac- 
tion of  the  tooth  or  extirpation  by  the  broach. 

The  efifect  of  twenty  minutes'  contact  of  an  inflamed  pulp  with 
the  poison,  in  a  tooth  of  a  patient  sixteen  years  of  age,  is  illus- 
trated in  Fig.  263. 

The  inflamed  zone  is  conspicuous  by  the  lack  of  the  stain  with 
ammoniacal  carmin,  which  feature  we  know  to  be  characteristic 


EFFECTS    OF   ARSENIC    UPOX    TOOTH-PULPS. 


521 


of  the  death  or  necrosis  of  the  tissues.  Only  the  walls  of  the 
blood-vessels  have  taken  up  the  stain,  which  fact  proves  that 
the  tissues  under  the  influence  of  circulating  blood  retain  life 
longer  than  those  away  from  the  blood-vessels.     The  inflamma- 


FiG.  263. 


Pulp  AFFECTED  BY  Acute  Pulpitis  treated  with  Arsexic  Dioxide  foe  Twextt  Minutes. 

P,  portion  of  pulp'in  acute  inflammation,  showing  effect  of  arsenic  dioxide  ;  Jf,  normal  myxo- 
matous pulp  ;  C,  capillaries  engorged  with  blood  ;  K,  bundle  of  meduUated  nerves.  Magnified 
500  diameters. 

tory  corpuscles  show  a  peculiar  gloss,  at  the  same  time  lacking 
■sharply-defined  contours.  The  same  happened  with  the  tracts 
of  spindles,  obviously  the  remnants  of  pre\Tious  blood-vessels. 
The  portions  nearest  to  the  non-inflamed  pulp  and  the  pulp  itself, 


522  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

being  of  a  distinct  myxomatous  structure,  appear  colored  with 
ammoniacal  carmin.  Tlie  blood-vessels  are  dilated  and  en- 
gorged with  blood-corpuscles,  showing  no  reaction  upon  the 
arsenic  dioxide.  The  medullated  nerves  are  broken  up  into 
inflammatory  corpuscles  in  the  region  of  pulpitis.  Farther 
down  the  myelin  is  segmented  in  a  manner  known  to  suc- 
ceed inflammation.  Since  it  seems  impossible  that  arsenic 
dioxide  should  have  produced  an  inflammatory  reaction  within 
twenty  minutes,  it  is  reasonable  to  say  that  in  this  case  life 
was  destroyed  particularly  in  the  inflamed  portions  of  the  pulp. 
At  the  same  time,  the  elements  had  been  preserved  in  size 
and  shape,  and  therefore  were  mummified. 

C.  Weigert*  has  proposed  to  term  such  a  condition  of  tissues 
and  elements  "  coagulation-necrosis."  This  term  seems  to  be 
applicable  whenever  heat  or  chemical  reagents,  such  as  strong 
solutions  of  corrosive  sublimate,  carbolic  acid,  chloride  of  zinc, 
etc.,  are  brought  in  contact  with  the  tissues,  combustion  of  the 
skin  and  mummification  of  the  pulp  being  good  examples. 
Serious  doubts  have  been  raised  by  good  observers  against  the 
propriety  of  the  term  "coagulation-necrosis"  as  proposed  by 
Weigert. 

In  a  number  of  pulps  treated  with  arsenic  dioxide  from  one  to 
twelve  hours,  no  evidence  of  necrosis  of  the  pulp-tissue  could 
be  obtained,  since  the  stain  with  ammoniacal  carmin  was 
present  and  the  appearance  of  mummification  absent.  An 
instance  of  diffuse  calcification  of  the  pulp  with  complete  mum- 
mification from  arsenic  dioxide  after  twenty-four  hours'  contact  is 
illustrated  in  Fig.  264.  This  pulp  was  removed  from  an  upper 
central  incisor  of  a  patient  about  sixty  years  of  age.  The 
crown  was  half  worn  away  by  mechanical  abrasion,  nearly 
approaching  the  pulp-chamber.  The  application  of  arsenic 
dioxide  was  made  for  the  purpose  of  devitalizing  the  pulp  in 
order  to  obtain  sufficient  anchorage  for  a  large  contour  gold 
filling.  The  pulp  was  extracted  by  means  of  a  broach.  Under 
the  microscope  a  large  portion  of  the  pulp  was  found  diffusely 
calcified.  The  pulp-tissue  still  showed  vestiges  of  structure, 
though  finely  granular  throughout.  Most  of  the  capillary  and 
venous  blood-vessels  were  found  crowded  with  clusters  of 
irregularly-outlined  blood-corpuscles  of  a  dusky  red-brown 
color.    The  perivascular  space  around  these  vessels  was  widened 

*  Deustehe  Med.  Wochensch?:,  1883. 


EFFECTS    OF    ARSENIC    UPON    TOOTH-PULPS. 


52S 


and  well  pronounced.  The  mednllated  nerves,  some  of  which 
entered  the  calcified  region  without  having  caused  pain,  were 
broken  up  into  small,  glossy,  irregularly-shaped  lumps,  the  same 


Fig.  264. 


;l::4::l::-i 


ilMfl'i" 


Pulp  affected  bt  Calcificatiox  treated  with  Arsexic  Dioxide  for  Tttexty-four 

HotTRS. 

D,  diffuse  deposits  of  lime-salts  ;  N,  bundle  of  medullated  nerves,  entering  the  calcified  por- 
tion of  the  pulp :  M,  bundle  of  medullated  nerves,  broken  up  by  arsenic  dioxide  ;  A,  axis-cylin- 
der, changed  by  arsenic  dioxide ;  C,  capillary  holding  changed  red  blood-corpuscles  ;  P,  P,  finely- 
granular  pulp-tissue.    Magnified  500  diameters. 

as  non-medullated  nerves,  still  traceable  here  and  there.  This 
feature  is  long  since  known  to  me  as  a  result  of  the  action  of 
arsenic  dioxide. 


524  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

In  the  Mgliest  degrees  of  mummification,  when  the  reagent 
has  been  left  in  situ  for  several  daj's,  the  pnlp-tissue  is  trans- 
formed into  a  yellowish-red,  glossy,  almost  waxy-looking  mass, 
in  which  the  tissue-elements  are  but  faintly  recognizable. 

My  experience  with  arsenic  dioxide  has  led  me  to  consider  it 
an  unreliable  agent,  often  causing  the  death  of  the  pulp  in  cir- 
cumscribed regions,  mainly  of  the  coronal  portion,  leaving  the 
root-portions  unaffected.  But  even  in  such  instances  the  root- 
portions  are  liable  to  die,  and  subsequently  become  a  source  of 
suppurative  pericementitis.  In  some  cases  no  reaction  whatso- 
ever follows  the  application  of  arsenic  dioxide ;  in  others  only 
pulpitis  is  brought  forth,  instead  of  mummification ;  in  still  other 
cases  the  action  is  too  far-reaching,  and  destroys  the  whole  of 
the  pulp,  the  crown  as  well  as  the  root-portions.  Exceptionally 
the  inflammatory  reaction  is  so  severe  that  pericementitis  sets 
in,  and  instances  are  on  record  in  which  extensive  gangrene 
followed  the  application  of  arsenic  dioxide. 

My  advice  in  regard  to  the  use  of  arsenic  dioxide  for  the  pur- 
pose of  devitalizing  the  pulps  of  teeth  is  to  employ  it  only  in 
exceptional  cases,  and,  if  possible,  discard  it  altogether.  When, 
however,  it  is  made  use  of,  this  should  only  be  done  in  normal 
or  in  acutely -iiijicuned  pulps.  In  all  cases  of  chronic  pulpitis,  and 
especially  in  hyperplasia  of  the  pulp,  arsenic  dioxide  should 
never  be  applied.  In  the  latter  instances  it  is  liable  to  produce 
a  very  acute  attack  of  pulpitis,  accompanied  by  excruciating 
pains,  and  usually  without  the  desired  result  of  devitalizing  the 
pulp. 

In  order  to  obviate  the  difficulties  of  filling  pulp-canals,  Wil- 
helm  Herbst,  of  Bremen,  Germany,  recommended  a  novel 
procedure.* 

The  methods  of  practice  observed  by  him  are  as  follows  : 
If  the  pulp  of  a  tooth  is  in  such  a  condition  that  it  becomes 
necessary  to  remove  it,  an  application  of  cobalt,t  to  which  has 
been  added  about  eight  per  cent,  of  hydrochlorate  of  cocaine, 
is  made  to  it,  and  covered  with  wax  or  some  other  temporary 
filling-material.  After  two  or  three  days  the  temporary  filling 
is  removed,  the  cavity  cleansed  from  all  decay,  and  rinsed  out 

*  "The  Herbst  Method  of  Treating  Pulps."     Dental  Cosynos,  1892. 
t  A  sample  of  cobalt,  sent  by  Dr.  Herbst,  was  examined  by  Dr.  E.  C.  Kirk, 
who  found  it  to  be  metallic  arsenic. 


EFFECTS    OF    ARSENIC    UPOX    TOOTH-PULPS.  525 

with  water.  Then,  if  practicable,  the  ruhber-clam  is  aclj listed, 
the  cavity  thoroughly  disinfected,  and  the  coronal  portion  of 
the  pulp  is  amputated  by  means  of  a  large,  perfectly  clean, 
sharp,  round  bur,  which  is  rapidly  revolved  in  the  hand-piece 
of  the  dental  engine.  The  bur  must  be  nearly  as  large  as  the 
coronal  portion  of  the  pulp  which  is  to  be  amputated.  The 
pulp-chamber  is  then  to  be  washed  out  with  a  solution  of  corro- 
sive sublimate  of  the  strength  of  one-tenth  of  one  per  cent.,  and 
dried.  A  cylinder,  or  a  loosely-rolled  ball  of  J^o.  4  tin  foil,  as 
large  as  the  cavity  will  admit,  is  now  placed  in  the  pulp- 
chamber  directly  over  the  amputated  pulp-stump,  and  with  a 
revolving,  smooth  burnisher,  which  is  smaller  than  the  j^ulp- 

FiG.  265. 


/, 


DiAGKAM  OF  Molar  treated  by  Dr.  Herbst. 
F,  filling  ;  B,  dentine  ;  E,  enamel ;  T,  tin  cap  ovei-  pulp-stumps  ;  P,  pulp  ;  C,  cementum. 

chamber,  the  tin  is  burnished  firmly  into  it.  In  burnishing, 
care  should  be  exercised  not  to  press  the  tin  directly  upon  the 
pulp-stump,  but  the  force  should  be  exerted  more  laterally. 
It  is  also  necessary  that  the  stumps  to  be  capped  in  this  manner 
be  not  irritated  with  small  burs,  excavators,  or  nerve-instru- 
mients,  as  failure  has  been  observed  in  those  cases  in  which  this 
was  done.  Herbst  also  advises  that  in  case  the  tooth  becomes 
sensitive  to  pressure  after  such  an  operation,  it  should  be  short- 
ened a  little,  and  the  filling  in  the  tooth  not  left  high  enough 
to  touch  the  antagonizing  tooth.  If  amalgam  is  employed,  it 
is  advisable  to  place  a  small  particle  of  wax  upon  the  tin  cap, 
and  distribute  it  over  the  surface  of  the  tin  by  means  of  the  rotat- 


526  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

ing  burnisher.  If  this  precaution  is  neglected,  the  mercury  of 
the  amalgam  will  combine  with  the  tin,  and  the  efficiency  of 
the  cap  be  destroyed. 

The  theory  entertained  by  Herbst  in  regard  to  this  treatment 
of  pulps  is  that  by  burnishing  tin  or  gold  into  the  pulp-cavity, 
he  creates  an  absolutely  air-tight  covering  to  the  root-canal, 
which  is  not  obtainable  with  other  materials.  Herbst  claims 
that  good  results  cannot  be  expected  by  the  use  of  amalgam, 
cement,  or  gutta-percha,  and  even  tin  and  gold  foils  introduced 
into  the  pulp-chamber  by  the  mallet  system  have  proved  to  be 
failures.  In  cases  of  front  teeth,  he  employs  gold  foil  instead 
of  tin, — as  he  claims,  with  equally  good  results. 

One  of  the  teeth,  an  inferior  molar,  which  Dr.  Herbst  sent  to 
me  for  examination,  was  amputated  and  capped  by  him  in  the 
manner  above  described  about  three  years  ago,  and  had  been 
in  a  normal  condition  until  it  was  extracted.  The  tooth  was 
removed  on  account  of  an  overcrowded  condition  of  the  dental 
arch,  as  well  as  to  obtain  a  specimen  for  examination.  Imme- 
diately after  extraction  it  was  immersed  in  dilute  alcohol,  in 
which  it  was  sent  to  this  country.  Upon  its  arrival  here  it  was 
placed  in  a  solution  of  chromic  acid  of  the  strength  of  one  per 
■cent.,  which  solution  was  renewed  every  day  until  the  dentine 
became  sufficiently  soft  to  be  sliced  by  the  microtome.  For 
staining,  an  ammoniacal  solution  of  carmin,  and  for  mounting, 
glycerin,  were  employed. 

A  longitudinal  section  through  the  crown  and  one  of  the 
roots  of  this  tooth  yielded  an  image  as  depicted  in  Fig.  266. 
In  the  pulp-cavity  of  the  crown  we  see  remnants  of  a  narrow 
zone  of  previously-inflamed,  necrotic  tissue.  The  outermost 
border  of  this  layer  is  conspicuous  because  of  the  presence  of 
black  metallic  particles,  probably  the  tin  foil  in  combination 
with  sulphur.  At  the  point  of  bifurcation  the  pulp  is  pre- 
served, though  changed  into  a  fibrous  connective  tissue  by  the 
process  of  chronic  plastic  pulpitis. 

In  this  fibrous  pulp  we  observe  small  spicules  of  bone-tissue. 
The  boundary  zone  between  the  pulp  and  the  dentine  shows 
narrow  rows  of  calcified  elongated  corpuscles,  similar  to  those 
which  we  often  observe  along  the  border  between  the  cementum 
and  pericementum  of  the  neck  and  the  roots  of  normal  teeth. 
The  border  of  the  pulp,  toward  the  pulp-cavity,  which  had  been 
filled  with  tin,  is  likewise  marked  by  metallic  particles,  which 


EFFECTS    OF    ARSENIC    UPOX    TOOTH-PULPS. 


527 


proves  that  the  tin  actually  has  been  in  contact  with  the  pulp- 
tissue. 

The  border  of  the  dentine,  both  in  the  crown  and  the  root, 


Fig.  266. 

S  CM 


im;/^m^  w^, 


mn 


I'l'f'iiii'Af 


wMk. 


J//{//^: 

'''l^vfrW///////la*«f 


///|/i!ij/,^VM(ii 


'd      V; 


.Section  of  Lo'R'eh  Molae  Boeder  of  Pulp-Chamber,  xeae  Bifurcation  of  Roots. 

D,  dentine,  canaliculi  cut  obliquely ;  jS,  secondary  changes  of  dentine  ;  C,  colonies  of  micro- 
cocci in  dead  pulp  ;  M,  black  particles  of  metal ;  P,  fibrous  pulp,  the  result  of  chronic  plastic 
pulpitis ;  0,  osteoid  layer  of  pulp  at  the  border  of  dentine ;  B,  spicule  of  newly-formed  bone. 
Magnified  100  diameters. 

is  of  considerable  interest.  In  the  crown  the  dentine  toward 
the  necrotic  pulp  is  thoroughly  calcified,  without  a  pronounced 
structure,  evidently  in  the  condition  of  consolidation  and  aug- 


528 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


merited  deposition  of  lime-salts,  such  as  we  often  observe  in 
dentine  bordering  metallic  fillings.  All  along  the  pulp-canal 
the  dentine  is  broken  up  into  small  globular  and  oblong  cor- 
puscles, obviously  the  result  of  a  previous  acute  eburnitis,  with 
subsequent  deposition  of  lime-salts.  This  peculiarly  altered 
zone  of  dentine  is  broadest  along  the  pulp-chamber  of  the 
crown,  and  gradually  tapers  along  the  pulp-canal  of  the  root, 
while  toward  the  apex  it  altogether  disappears. 

A  portion  of  this  wall  of  the  pulp-chamber  of  the  crown  is 


Fig.  267. 


■tnt,.>:k'^i^'t 


Boeder  of  Pulp-Chamber  of  the  Crown. 

M,  black  particles  of  metal  at  the  surface ;  N,  necrotic  vestiges  of  non-medullated  nerves ; 
P,  necrotic  remnants  of  the  pulp;  T,  thickness  of  specimen,  succefsive  layers  of  dentine;  B, 
border  of  dentine,  with  gaping  dentinal  canaliculi ;  0,  region  of  obliterated  dentinal  canali- 
culi ;  C,  pointed  ends  of  dentinal  canaliculi.    Magnified  500  diameters. 

illustrated  in  Fig.  267.  Here  we  observe  a  layer  of  necrotic 
pulp-tissue,  with  metallic  particles  at  the  outermost  periphery. 
The  pulp,  before  it  became  necrotic  by  the  action  of  cobalt, 
must  have  been  in  a  condition  of  intense  acute  pulpitis,  which 
is  proved  by  the  presence  of  numerous  vestiges  of  inflammatory 
corpuscles.  The  necrotic  pulp  shows  even  remnants  of  non- 
medullated  nerve-fibers,  likewise  in  a  granular  disintegrated 
condition. 


EFFECTS    OF    ARSEXIC    UPON    TOOTH-PULPS. 


529 


In  some  of  my  specimens,  in  the  dead  pulp  I  could  trace  colo- 
nies of  micrococci,  developed  during  the  process  of  pulpitis, 
and  deprived  of  life  and  rendered  innocuous  by  the  application 
of  cobalt  and  contact  with  the  tin. 

In  that  portion  of  dentine  depicted  in  Fig.  267  a  zone  is  miss- 
ing. The  dentine  borders  the  dead  pulp  in  an  abrupt  line,  con- 
spicuous by  regular,  though  widened  and  funnel-shaped,  den- 
tinal canaliculi.     It  seems  probable  to  me  that  the  widening  of 

Fig.  268. 


;f-.i^''^rfCr^.A;,:??«:g 


■  "Va)  . 


m 


'Jh^lr 


iillPfliiit 

iiilteliiill  1 


liiliiiliMiilfii^ 


Border  op  PtiLP-CHAifBER  op  the  Crown. 

P,  protoplasmic  layer  of  inflamed  pulp;  C,  zone  of  consolidation  of  dentine;  Z*,  dentine, 
with  canaliciili  without  deposits ;  P,  dentine  in  which  the  canaliculi  are  loaded  with  metallic 
particles.    Magnified  500  diameters. 

the  canaliculi  is  the  result  of  an  acute  pulpitis,  which  did  not 
last  long  enough  to  induce  pronounced  changes  in  the  tissue  of 
the  dentine.  The  border  zone  of  the  dentine  is  granular,  and 
followed  by  a  zone  of  consolidation  in  which  the  dentinal  can- 
aliculi have  completely  disappeared.  Possibly  the  whole  bor- 
der of  the  dentine  toward  the  necrotic  pulp  is  devitalized  down 
to  the  region  in  which  dentinal  canaliculi  and  unchanged  den- 
tinal fibers  are  observed.     The  pulp  of  the  crown,  however,  is. 

35 


530 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


not  altogether  uecrotic;  there  are  portions  within  the  crown 
still  supplied  with  a  narrow  layer  of  living  pulp,  as  shown  in 
Fig.  268. 

These  vestiges  of  the  pulp  are  broken  up  into  protoplasmic 
bodies,  which  in  part  have  become  the  seat  of  calcareous  deposits. 
The  only  way  to  explain  this  remarkable  feature  is  that  a  thin 
film  of  the  inflamed  pulp  has  escaped  both  the  process  of  cauter- 
ization with  cobalt  and  destruction  by  the  amputation.     The 

Tig.  269. 


mif3^pf%t^§3tm 


-yS 


^*Cy% 


s »  K 


'J 


Border  of  Root-Canal. 

P.  fibrous  pulp,  the  result  of  chronic  plastic  pulpitis;  0,  calcified  layer  of  pulp;  B,  border  of 
dentine;  6^,  granular  layer  of  dentine  ;  0,  layer  with  obliterated  dentinal  canaliculi.  Magni- 
fied 500  diameters. 


zone  of  dentine  nearest  to  the  pulp  is  consolidated,  as  shown  by 
its  high  refraction  under  the  microscope;  but  even  this  con- 
solidated portion  is  pierced'  by  unchanged  dentinal  canaliculi 
holding  normal  dentinal  fibers.  The  dentine  along  the  pulp- 
chamber  of  the  crown  in  many  instances  exhibits  a  peculiar 
black  discoloration,  which  I  have  often  observed  in  dentine  that 
has  been  in  contact  with  an  amalgam  filling.  Strange  as  it  may 
appear,  it  is  nevertheless  a  fact  that  the  discoloration  does  not 
start  from  the  border  of  the   dentine,  bat  a   certain   distance 


EFFECTS    OF    ARSENIC    UPON    TOOTH-PULPS. 


531 


away  from  it.  As  shown  in  Fig.  268,  the  discoloration  is  caused 
by  the  presence  of  metallic  particles,  lying  as  if  arranged  in  rows 
within  the  dentinal  canaliculi,  and  by  the  diffused  brown  pig- 
mentation of  the  basis-substance  between  the  canaliculi.  The 
latter  color  is  most  intense  in  an  abrupt  line,  irregular  in  itself, 
toward  the  pulp-chamber.  The  peculiar  discoloration  is  explic- 
able only  by  admitting  a  transportation  of  metallic  particles  by 
the  dentinal  fibers,  a  strong  proof  of  the  life  of  both  the  dentinal 
fibers  and  the  basis-substance  of  the  dentine. 

Fig.  270. 


Ossification  of  Fibeocs  Pulp. 

F,  coarse  bundles  of  fibrous  pulp,  derived  from  chronic  plastic  pulpitis ;  B,  spicula  of  bone, 
with,  bone-corpuscles  ;  C,  calcification  of  pulp-tissue  preceding  ossification  ;  M,  medullary  tissue. 
Magnified  500  diameters. 


I  hare  stated  before  that  the  pulp  of  the  root-canals,  begin- 
ning from  the  point  of  bifurcation,  is  transformed  into  fibrous 
connective  tissue.  The  nature  of  this  transformation  is  rendered 
clear  by  higher  powers  of  the  microscope.     (See  Fig.  269.) 

The  pulp-tissue  is  really  made  up  of  bundles  of  fibrous  con- 
nective tissue,  almost  as  broad  as  those  of  pericementum,  peri- 
osteuna,  or  the  derma  of  the  skin.  Between  the  bundles  we 
notice  interstices  of  varying  breadth  filled  with  protoplasm,  as 


532  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

we  always  observe  in  formations  of  iibrous  connective  tissue. 
The  bundles  toward  the  dentine  terminate  in  calcified,  elongated 
clusters,  correspondiug  on  an  average  with  the  breadth  of  the 
bundles  themselves.  The  most  striking  feature  is  that  the 
interstices  between  the  calcified  lumps  and  the  bundles  above 
these  lumps  contain  fibers  similar  to  dentinal  fibers.  The 
border  of  the  dentine  toward  the  fibrous  pulp  is  slightly  con- 
solidated,— that  is,  somewhat  richer  in  lime-salts  than  the  rest  of 
the  dentine.  This  consolidated  layer  is  followed  by  a  granular 
one,  which  is  scantily  provided  with  lime-salts,  containing 
vestiges  of  dentinal  canalicnli.  Next  follows  a  layer  of  dentine 
in  which  the  dentinal  canaliculi  are  obliterated,  which  a  little 
farther  away  appear  with  pointed  ends  holding  normal  fibrill?e. 
In  Fig.  266  is  illustrated  a  small  spicula  of  bone  in  the  pulp- 
tissue,  which  is  of  considerable  interest  when  studied  with 
higher  powers  of  the  microscope.     (See  Fig.  270.) 

Here  we  observe  normally  developed  bone-tissue,  but  lacking 
Haversian  canals  and  regular  lamellae.  We  also  see  the  manner 
in  which  bone-tissue  is  developed  from  the  fibrous  connective 
tissue  of  the  pulp.  This  is  accompliished  by  the  intervening 
formation  of  a  medullary  or  embryonal  tissue  (see  M),  from 
which  the  bone-corpuscles,  as  well  as  the  basis-substance  of  the 
bone-tissue,  are  forming.  The  formation  of  bone  is  not  of  uni- 
form progress  all  around  this  spicula,  as  we  observe  a  bordering 
of  the  bone  by  a  fibrous  tissue,  in  some  places  unchanged,  in 
others  slightly  reduced  to  protoplasm.  The  transformation  of 
the  medullary  into  the  bone-tissue  is  not  always  an  immediate 
one.  In  some  places  we  notice  calcified  groups  of  medullary 
corpuscles  (see  C)  preceding  ossification.  Unquestionably  the 
lime-salts  of  such  clusters  must  be  dissolved  out  again  before 
the  final  appearance  of  the  bone-tissue  proper. 

The  microscopical  analysis  of  this  molar  is  of  considerable 
biological  importance.  The  dentine  was  found  alive,  its  fibers 
unchanged  throughout  the  crown  and  the  roots,  except  a  narrow 
zone  which  bordered  the  portion  of  necrotic  pulp.  This  result 
is  explicable  only  by  the  fact  that  the  pulp  of  the  roots,  although 
changed  in  structure,  is  still  alive.  The  proof  of  this  assertion 
is  furnished  by  examining  the  specimens  with  high  powers  of 
the  microscope,  as  seen  in  Fig.  271. 

We  observe  all  the  bundles  of  the  fibrous  connective  tissue 
traversed   by  a   delicate    reticulum,  without  resorting  to  any 


EFFECTS    OF    ARSENIC    UPOX    TOOTH-PULPS. 


533 


special  staining  process.  This  reticulum  of  living  matter  inos- 
culates with  the  protoplasm  between  the  bundles,  and  with  the 
:fi.bers  which  appear  like  dentinal  fibrillee  in  the  interstices 
between  the  bundles.  A  similar  reticulum  is  noticeable  in  the 
consolidated  as  well  as  in  the  granular  layers  of  tbe  dentine. 
Obviously,  the  living  pulp  of  the  roots,  assisted  by  the  nutri- 
tion derived  from  the  pericementum,  kept  the  dentine  of  the 
whole  tooth  alive.  If  the  dentinal  fibers  in  the  canaliculi  were 
the  only  living  formations  of  the  dentine,  nothing  but  the  den- 

FiG.  271. 


Border  of  Dentine  of  Root  toa'ard  the  Pulp. 

<?,  granular  layer  of  dentine ;  C,  thoroughly-calcified  layer  of  dentine ;  F,  fibrous  pulp 
made  up  of  coarse  bundles.    Magnified  1000  diameters. 


tine  of  the  roots  could  have  remained  alive  after  the  destruction 
of  the  coronal  portion  of  the  pulp  in  the  crown  of  the  tooth. 
Since,  however,  the  whole  of  the  dentine  has  remained  alive, 
we  have  another  strong  proof  of  interconnections  between  the 
dentinal  fibers.  These  interconnections  are  established  by  the 
delicate  reticulum  of  living  matter  pervading  the  basis-substance 
of  the  dentine. 

Another  lower  molar  was  sent  to  me  bv  Dr.  Herbst.     It  had 


534  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

remained  in  the  mouth  about  eighteen  months  after  the  pulp 
had  been  amputated  and  capped  in  the  manner  before  described. 
The  tooth  had  given  no  trouble  since  the  operation,  and  was 
extracted  for  the  same  reason  as  the  one  described  above. 

This  tooth  was  not  decalcified  in  a  solution  of  chromic  acid, 
but  split  into  several  pieces  by  excising  forceps,  and  ground  thin 
upon  a  corundum-wheel  in  the  lathe,  constantly  keeping  it 
under  an  aqueous  solution  of  table-salt. 

The  roots  of  this  tooth  contained  but  a  narrow  mass  of  pulp- 
tissue,  crowded  with  globular  deposits  of  lime-salts,  and  in  the 
process  of  formation  of  secondary  dentine.  The  latter  was 
found  developed  all  along  the  walls  of  the  root-canals  in  a 
heavy  mass,  interposed  between  the  primary  dentine  and  the 
remnants  of  pulp-tissue.  It  consisted  of  the  most  common 
variety, — viz,  wavy  and  irregular  canaliculi,  traversing  the  basis- 
substance.  The  production  of  such  secondary  dentine  from  the 
pulp-tissue  of  the  roots  is  a  strong  proof  of  the  life  of  the  pulp, 
which,  having  been  irritated  less  than  the  tooth  first  described, 
directly  led  to  the  formation  of  secondary  dentine. 

In  conclusion,  I  would  advise  to  remove  the  pulps  from  those 
roots  which  we  know  can  be  prepared  easily,  and  treat  them  in 
the  manner  we  have  been  accustomed  to,  but  amputate  and  cap 
the  others. 


CHAPTEE    XLII. 

NECROSIS    OF    THE   JAW-BONES. 


Whenever  purulent  pericementitis  sets  in,  there  is  danger  of 
the  inflammation  spreading  to  the  adjacent  periosteum  and 
causing  necrosis  or  death  of  the  jaw-bone.  In  previous  years 
the  idea  prevailed  among  pathologists  that  by  the  intense 
inflammatory  infiltration  of  the  periosteum  the  blood-vessels 
were  compressed  and  rendered  unfit  for  carrying  nutrient 
material  to  the  jaw-bones.  To-day  we  know  that  the  discon- 
tinuance of  blood-supply  is  not  due  to  a 'Compression  of  the 
vessels,  but  to  a  breaking  up  of  the  walls  of  the  blood-vessels 
first  into  inflammatory,  afterward  into  pus-corpuscles.  As  shown 
in  Chapter  XXXIX,  the  capillaries  and  veins  become  obliter- 


NECKOSIS    OF    THE    JAW-BOXES.  635 

ated  by  a  proliferation  of  tlieir  endothelial  coat ;  the  same  holds 
good  for  small  arteries,  the  endothelia  here  being  involved  first, 
and  followed  by  inflammation  of  the  muscle-coat.  As  soon  as 
a  breaking  asunder  of  the  inflammatory  into  pus-corpuscles 
takes  places,  all  vestiges  of  such  blood-vessels  disappear. 

If.  in  a  certain  area,  the  blood-vessels  in  the  periosteum  and 
in  the  medulla  of  the.bone  are  destroyed,  life  of  the  bone  ceases  ; 
or  in  other  words,  the  bone-tissue  corresponding  to  the  extent 
of  the  bloodless  area  becomes  necrotic. 

In  the  mildest  cases  of  purulent  periostitis,  the  wall  of  the 
alveolus,  or  portions  thereof,  may  become  necrotic.  In  severe 
cases  the  body  of  the  jaw-bone  may  die;  in  the  worst  instances 
the  purulent  periostitis  suddenly  or  gradually  attacks  the 
whole  jaw-bone,  especially  the  lower  one.  Xot  infrequently 
life  is  endangered  by  the  spreading  of  the  suppuration  from  the 
upper  jaw-bones  to  the  base  of  the  skull,  with  subsequent  puru- 
lent meningitis  and  encephalitis.  From  the  lower  jaw  the 
inflammation  may  extend  into  the  mediastina,  causing  abscesses, 
purulent  pleuritis,  pericarditis,  etc.  Another  .source  of  fatal 
termination  is  the  formation  of  pyaemic  abscesses  in  the  lungs, 
the  liver,  etc.  All  these  terminations  were  far  more  common 
in  tissues  when  asepsis  was  unknown,  and  cases  are  on  record 
in  which  the  extraction  of  a  tooth  with  an  unclean  pair  of 
forceps  had  sufficed  to  produce  purulent  or  septic  periostitis  of 
the  jaw-bone,  with  subsequent  pyaemia  and  the  death  of  the 
patient  in  a  comparatively  short  space  of  time.  To-day  aseptic 
precautions  being  used  by  all  intelligent  dentists  and  surgeons^ 
such  accidents  have  become  great  rarities. 

Staphylococcus  (aureus,  albus,  and  citreus)  is  known  to  be  the 
cause  of  suppuration,  if  invading  an  already-inflamed  tissue.  A 
rapidly-progressing  suppuration  easily  terminates  in  gangrene 
of  the  inflamed  periosteum,  so-called  '•^ gangrene  foudroyante" 
of  the  French,  which  probably  is  caused  by  a  mixed  infection 
with  staphylococcus  and  streptococcus  septicus,  of  which  latter 
as  yet  little  is  known. 

Besides  purulent  pericementitis,  the  most  common  cause  of 
necrosis  of  the  jaw-bones  in  previous  years  was  the  inhalation 
of  the  vapors  of  phosphorus  in  match-factories.  It  is  an  estab- 
lished fact  that  only  the  workers  with  carious  teeth  were 
exposed  to  purulent  periostitis.  Since  the  introduction  of  ven- 
tilation and  other  sanitary  measures,  and  since  the  care  of  the 


536  THE    AXATOMY    AXD    PATHOLOGY    OF    THE    TEETH. 

teetli  is  stringently  carried  out  in  match-factories,  tlie  so-called 
pliosphorus-necrosis  has  become  of  rare  occurrence.  Purulent 
pericementitis  is,  however,  of  common  occurrence,  and  in  every 
instance  a  source  of  possible  purulent  periostitis  and  necrosis 
of  the  jaw-bones. 

Diagnosis. — Kecrosis  manifests  itself  by  the  sensation  of 
roughness,  when  a  probe  or  another  suitable  instrument  is 
brought  in  contact  with  the  bone.  The  surface  of  dead  bone 
always  is  denuded  of  periosteum,  and  consequently  appears 
rough,  similar  to  the  surface  of  a  piece  of  wood  sawed  across 
its  grain,  while  normal  bone  to  the  touch  of  an  instrument  is 
smooth  like  velvet.  A  diagnosis  of  the  extent  of  the  necrosis 
cannot  be  established  either  by  the  probe  or  by  the  naked  eye. 
The  gum  and  the  periosteum  over  necrosed  bone  always 
appears  inflamed,  detached  from  the  bone,  and  upon  pressure 
pus  oozes  forth.  One  of  the  principal  characteristics  of  the 
presence  of  necrotic  bone  from  local  origin  is  that  pus  forms 
continually,  even  though  the  original  source  of  irritation  be 
removed.  In  such  eases,  local  treatment  is  sufficient  for  a  cure. 
"When  the  necrosis  is  depending  upon  constitutional  derange- 
ments, such  as  syphilis  or  tuberculosis,  etc.,  it  will  subside  only 
upon  a  combined  constitutional  and  local  treatment. 

Subjective  Phenomena. — In  mild  cases  of  local  necrosis  of  the 
jaw-bones  the  patient  sutlers  no  pain,  the  only  annoyance  being 
the  constant  flow  of  pus  from  the  fistulous  opening.  The  teeth 
which  produced  the  trouble  may  be  still  involved  in  the  inflam- 
matory process,  but,  although  loose,  they  cause  no  pain.  In 
extensive  cases,  however,  especially  those  depending  upon 
syphilis,  tuberculosis,  or  the  inhalation  of  the  vapors  of  phos- 
phorus, the  patient  may  sufl:er  pain,  if  the  inflammation  involves 
either  the  superior  or  the  inferior  maxillary  branches  of  the 
fifth  pair  of  nerves.  Besides  this,  the  constant  discharge  of  foetid 
pus  often  causes  a  derangement  of  the  digestive  organs,  and 
consequently  of  the  general  constitution.  The  necrotic  process, 
if  extensive  and  acute,  invariably  is  accompanied  by  intense 
swelling  and  pain  of  the  aftected  region  and  by  high  degrees  of 
fever.  In  a  slowly-progressing  purulent  periostitis  only  the 
swelling  and  dull  pains  may  be  conspicuous,  without  a  pro- 
nounced febrile  derangement. 

Differential  Diagnosis. — There  is  but  one  disease  with  which 
necrosis  of  the  jaw-bone  may  be  confounded, — viz,  chronic  alve- 


NECROSIS    OF    THE    JAW-BOXES.  537 

oiar  abscess.  In  most  of  the  cases  of  local  origin,  chronic  alve- 
olar abscess  is  associated  with  or  followed  bj  the  necrotic  pro- 
cess. In  the  beginning  of  the  necrosis  an  examination  by 
means  of  the  probe  will  always  clear  the  diagnosis. 

The  pi'ogjiosis  of  necrosis  of  the  jaw-bones  largely  depends 
upon  its  extent,  its  acute  or  chronic  course,  and  the  general 
constitution  of  the  patient.  The  dental  practitioner,  if  called 
upon  to  treat  such  a  case,  is  in  a  great  measure  responsible  for 
the  final  favorable  or  unfavorable  termination.  The  pus  pours 
forth  from  the  sockets  around  the  roots  of  the  teeth,  and  the 
latter  soon  become  loose.  Some  practitioners  are  in  the  habit 
of  extracting  all  such  loose  teeth,  with  the  view  of  furnishing 
free  exit  to  the  pus  and  checking  the  progress  of  the  disease. 
This  practice  is  not  always  advisable,  since  we  know  that  loose 
teeth  after  the  removal  of  the  sequestrum  (necrotic  bone)  have 
become  firm  again  by  being  implanted  in  the  newly-formed 
bone-tissue  produced  by  the  remnants  of  periosteum,  and  serve 
for  mastication  again,  at  least  for  a  number  of  years. 

I  have  seen  many  cases  of  partial  necrosis  of  the  jaw-bones 
from  purulent  periostitis  induced  by  a  root  of  a  tooth.  In  one 
instance,  that  of  a  lower  molar,  the  two  roots  were  laid  bare 
by  necrosis  of  a  portion  of  the  socket,  while  the  lingual  portion 
of  the  root  remained  firm  and  rendered  the  tooth  serviceable  for 
"twelve  years,  when  at  last  it  was  destroyed  by  caries. 

Conservative  surgery  is  decidedly  in  place  in  every  case  of 
necrosis.  ISTo  surgeon  is  able  to  find  out  the  limits  of  the 
disease  until  nature  has  circumscribed  the  process.  Chiseling, 
drilling,  nor  treatment  with  aromatic  sulphuric  acid  will  ever 
check  the  process.  After  a  complete  sequestration  of  the  cen- 
tral necrotic  bone,  the  opening  of  the  newly-formed  ossified 
•case  is  an  easy  matter,  and  we  know  that  after  so-called  necrot- 
omy of  the  whole  lower  jaw-bone  a  fairly  well-formed  new 
jaw-bone  may  be  produced,  with  most  of  the  teeth  preserved. 
(J.  R.Wood.) 

A.  Lorinser,  of  Vienna,  about  fifty  years  ago,  was  the  first 
to  accurately  describe  the  necrosis  of  the  jaw-bones  from  phos- 
phorus-poisoning. From  a  large  experience  in  these  cases,  he 
strictly  urged  the  so-called  conservative  plan  of  treatment. 
Eecently  he  found  support  by  E.  Eose,  of  Berlin,*  for  all  cases 

*  "  Das  Leben  der  Zahne  ohne  "Wurzeln."  Deutsche  Zeitsch.  fur  Chirurgie^ 
Bd.  XXY,  1887. 


538  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

of  inflammations  terminating  in  necro&is  of  the  jaw-bones.  This 
author  claims  that  the  teeth  may  be  saved  even  Avhen  held  in 
place  only  by  the  gums,  and  are  wiggling  like  the  stalks  of 
wheat  in  the  wind,  the  roots  being  perfectly  bare.  He  asserts 
that  the  life  of  the  teeth  may  remain  preserved  through  the 
attached  gums.  In  this  he  unquestionably  is  mistaken.  The 
serviceability  of  the  teeth,  after  their  impaction  in  newly-formed, 
bone,  does  not  depend  upon  their  life,  but  upon  their  firmness. 
The  final  conclusions  of  his  article  are  as  follows:  "In  all  in- 
flammations of  the  lower  jaw  of  a  dubious  nature,  we  will 
hereafter  preferably  make  the  incision  from  below,  to  save  the 
gums  at  all  events ;  chisel  all  bone-cases  of  the  jaw  from  the 
lower  surface,  and  extract  the  dead  jaw,  as  it  were,  from  the 
teeth.  The  wiggling  of  the  teeth  never  ought  to  induce  us  ta 
their  hasty  extraction.  We  thus  will  be  rewarded  by  having 
all  teeth  fixed  in  the  newly-formed  jaw,  useful  as  ever." 

The  histology  of  necrotic  bone  I  have  published  many  years 
ago.*  As  to  the  microscopical  difl:erences  between  normal  and 
necrotic  bone,  the  successful  study  of  the  elements  of  bone- 
tissue  much  depends  upon  the  method  employed.  I  have  fol- 
lowed the  methods  of  examination  of  bone-tissue  after  decalci- 
fication in  solution  of  chromic  acid.  This  enabled  me,  by  the 
use  of  the  razor,  to  obtain  sections  fit  to  be  examined  by  an 
immersion-lens  magnifying  800  to  1000  diameters.  I  noticed 
that  the  canaliculi  could  be  plainly  seen  in  sections,  the  basis- 
substance  of  which  had  retained  a  small  quantity  of  lime- 
salts  ;  in  completely-decalcified  specimens  they  are  but  faintly 
discernible.  According  to  my  experience,  it  is  better  to  stain 
the  sections  with  a  solution  of  chloride  of  gold  of  the  half  of 
one  per  cent.,  whereby  a  better  view  of  both  protoplasm  and 
basis-substance  is  obtained.  Another  good  way  is  to  stain  the 
sections  with  carmin  and  hsematoxyliu. 

The  results  of  my  observations  with  high  magnifying  powers 
are  that  the  bone-tissue  presents  faint  parallel  lines,  dividing  it 
into  the  so-called  lamellse,  within  which  we  find  the  bone-cor- 
puscles of  varying  shapes.  As  bone-corpuscles  are  flattened 
lenticular  bodies,  we  will  recognize  them  in  this  shape  in  the 
front  view  only.  Longitudinal  sections  through  these  bodies 
give  a  spindle-shaped  outline,  small  when  cut  near  the  boun- 
dary, broad  when  cut  through  the  middle  line  of  the  lentil. 

*"  Necrosis. "     Dental  Cosmos,  1^11. 


NECROSIS    OF    THE    JAW-BONES.  539 

A  cross-section  through  a  bone-corpuscle  shows  a  somewhat 
irregular  body.  A  cross-section  from  the  compact  bone  of  a 
lower  jaw  presents  invariably  bone-corpuscles  in  all  three 
varieties. 

Fig.  272  shows  three  bone-corpuscles,  from  the  lower  jaw 
of  a  man  about  thirty  years  of  age,  who  died  of  an  aneurism. 
All  three  bone-corpuscles  are  drawn  in  the  front  view. 

"We  see  three  large  spaces,  showing  a  number  of  ray-shaped 
oiFshoots.  Besides  these  coarse  offshoots,  innumerable  extremely 
fine  light  ones  are  present.  The  larger  as  well  as  the  smaller 
ones  interconnect  by  this  delicate  net-work  throughout  the 
basis-substance.     Within  the  three  lacunse  are  present  proto- 

FiG.  272. 


^g,«^,Hi=5'AfjJS-i'->«S3"0?^'SS'BC3^jS., 


4Q 
M 


Normal  Boxe-Tissue  of  the   Lower  Jaw  of  a  Man  aged   Thirty  Years.     Chromic 
Acid  Specimen,  Stained  m^ith  Chloride  of  Gold. 

Three  bone-corpuscles  :   P^,  with  an  oblong  nucleus;  P^,-^^}!  a  globular  nucleus,  both  ex- 
hibiting indistinct  nucleoli ;   P^,  with  a  small  compact  nucleus.   Magnified  1000  diameters. 

plasmic  bodies.  "W  e  observe  in  the  center  of  the  protoplasmic 
bodies  P^  and  JP^  a  shining  oblong  nucleus  in  P\  and  a  round 
one  in  P^,  in  which  the  nucleoli  are  not  distinctly  visible. 
Around  the  nuclei  we  see  a  narrow  seam,  traversed  by  numer- 
ous fine  conical  threads.  Their  bases  are  directed  toward  the 
nucleus,  from  the  periphery  of  which  they  arise,  while  their 
points  are  in  connection  with  the  nearest  granules  of  the  proto- 
plasm. TVithin  the  protoplasmic  substance  there  are  finer  and 
coarser  gi^anules,  all  being  interconnected  by  fine  threads.  The 
seam  around  the  nucleus,  as  well  as  the  spaces  between  the 
meshes  of  the  threads,  are  observable,  being  much  lighter  than 
the  latter. 


540  THE    AXATOMY   AND    PATHOLOaY    OF    THE    TEETH. 

From  the  periphery  of  the  protoplasmic  body  numerous  thick 
offshoots  enter  the  larger  canaliculi,  which  sometimes  can  be 
followed  up  until  they  communicate  with  the  other  large  neigh- 
boring canaliculi.  Besides  these,  many  delicate  offshoots  run 
from  the  periphery  of  the  protoplasm  contained  in  the  larger 
canaliculi  toward  the  basis-substance.  Some  of  them  can  be 
seen  to  enter  the  fine  canaliculi,  but  their  course  cannot  be  dis- 
tinctly followed.  P^  shows  a  protoplasmic  body  without  nucleus ; 
probably  this  has  been  cut  near  to  its  periphery  without  touch- 
ino;  the  nucleus.  Thouo-h  I  am  not  able  to  demonstrate  the 
presence  of  living  matter  in  the  finest  canaliculi,  yet,  as  we  find 
it  in  all  other  kinds  of  connective  tissue,  I  am  justified  in  assum- 
ing it.  In  normal  bone  the  lacunae  and  canaliculi  are  not 
entirely  filled  b}^  the  living  protoplasm.  At  the  periphery  of 
each  protoplasmic  body  we  see  a  distinct  light  seam,  traversed 
by  the  offshoots,  which  in  a  cross-section  only  show  the  living 
part  of  the  protoplasm  in  the  center  of  the  canaliculus,  hence 
leaving  sufiBcient  space  for  the  nutrient  circulation. 

The  minute  changes  of  necrotic  bone  are  highly  interesting, 
but  it  is  impossible  to  study  the  difference  between  it  and  normal 
bone  in  specimens  prepared  from  dr}-  osseous  tissue. 

The  methods  employed  were  exactly  the  same  as  before 
described  from  normal  bone.  The  necrotic  sequestra,  as  soon 
as  they  had  been  taken  from  the  mouth,  were  put  into  the  solu- 
tion of  chromic  acid,  and  cut  in  due  time.  Some  I  stained  with 
chloride  of  gold,  some  with  hematoxylin,  and  some  I  mounted 
unstained. 

The  results  of  these  examinations  were  as  follows : 

The  outer  surface  of  the  necrotic  bone,  which,  to  the  naked 
eye,  looked  rough  and  eaten  out,  when  brought  under  the  micro- 
scope showed  bay-like  excavations,  known  formerly  as  "  How- 
ship's  lacunae,"  in  which  there  was  visible  a  granular  mass 
mixed  with  pus-corpuscles.  In  the  middle  of  the  bone  I  found 
all  the  Haversian  canals  more  or  less  enlarged,  some  showing  the 
bay-like  excavations.  The  contents  of  the  Haversian  canals 
were  everywhere  the  same, — a  conglomerate  mass  of  darkly- 
shaded  granules,  which  I  was  unable  to  stain  with  carmin ; 
therefore  micro-organisms,  such  as  we  see  in  decomposition  of 
organic  matter, — "  micrococci."  Here  and  there  some  medullary 
corpuscles  and  multinuclear  protoplasmic  bodies  (myeloplaxes 
of  Robin,  giant-cells  of  Yirchow)  were  recognizable.     I  did  not 


NECROSIS    OF    THE    JAAY-BONES.  541 

see  blood-vessels  in  any  of  the  Haversian  canals.  In  the  necrotic 
bone  I  found  the  traces  of  former  osteitis.  The  enlargement  of 
the  Haversian  canals  and  lacunse  is  direct  proof  of  this ;  the 
dissolving  out  of  the  basis-substance  on  the  periphery  may,  on 
the  contrary,  have  been  due  to  chemical  changes,  produced  by 
infiltrations  from  the  neighboring  inflamed  tissues.  Billroth 
has  shown  that  if  pieces  of  bone  or  ivory  are  driven  into  living 
bone,  in  which  they  excite  inflammation,  they  will  afterward 
exhibit  a  peculiar  dissolution  of  basis-substance  analogous  to 
that  which  we  see  in  the  primary  stage  of  inflammation.  The 
Haversian  systems  and  concentric  lamellse  were  unchanged. 
The  lacunae  and  canaliculi  were  yet  preserved.     In  preparations 


Fig.  273. 


--r^LS 


Xeceotic  Bone-Tissue  of  the  Loader  Jaw  of  a  Womax  aged  Thirty-eight 
Years.    Chromic-Acid  Specimen,  Stained  witk  Chloride  op  Gold. 

Three  lacunge :  X\  with  two  clusters  of  a  granular  mass ;  L-,  with  scanty  granules  ;  L^,  with 
a  nearly  homogeneous  mass.    Magnified  1000  diameters. 

from  the  necrotic  lower  jaw  I  observed  many  lacunae,  in  which 
the  protoplasmic  body,  with  its  living  net-work,  was  yet  distin- 
guishable, especially  where  the  sequestrum  had  been  attached  to 
the  periosteum.  I  found  also,  in  specimens  fi'om  the  necrotic 
upper  jaw,  some  comparatively  unchanged  bone-corpuscles. 
But  the  majority  of  the  bone-corpuscles,  and  especially  in  the 
neighborhood  of  the  Haversian  canals,  were  either  empty,  or 
their  protoplasmic  bodies  were  shriveled  up  (probably  the 
remains  of  the  living  matter),  only  showing  a  few  coarse 
granules,  illustrated  in  Fig.  273;  but  no  signs  of  fatty  degen- 
eration could  be  seen,  for  the  granules  were  stained  violet  by 
chloride  of  gold.     Many  lacunae  showed  no  structure  at  all,  the 


542  THE    AXAT03IY    A:\'D    PATHOLOaY    OF    THE    TEETH. 

•conteuts  looking  rather  like  a  mass  of  coagulated  albumin.  In 
none  of  these  lacunse  was  the  characteristic  structure  of  proto- 
plasm recognizable. 

To  sum  up  my  observations,  I  found, — 

First,  The  lacunas  of  normal  bone  contain  a  protoplasmic 
bodj',  with  a  net-like  arrangement,  to  be  regarded  as  the  living 
matter  of  the  protoplasm. 

Second.  The  basis-substance  is  pierced  by  numerous  coarse 
and  tine  canaliculi,  communicating  with  one  another,  as  well  as 
with  the  lacunae. 

Third.  The  protoplasmic  bodies,  which  do  not  quite  fill  the 
lacunsB,  send  ofl:shoots  of  the  living  substance  into  the  canali- 
culi, but  can  only  be  seen  in  the  coarser  ones. 

Fourth.  In  necrotic  bone,  traces  of  former  osteitis  are  visible, 
but  no  blood-vessels  in  the  Haversian  canals,  which  are  filled 
with  micrococci. 

Fifth.  In  necrotic  bone,  most  of  the  lacunae  contain  no  proto- 
plasm, but  either  a  coarsely-granular  or  a  structureless  mass, — 
remnants  of  the  livins:  matter  and  coagulated  albumin. 


CHAPTER   XLIII. 

EMPYEMA  OF  THE  AXTRUM. 


This  term  implies  a  chronic  inflammatory  condition  of  the 
mucous  membrane  lining  the  antrum,  and  an  accumulation  of 
serum  and  mucus  mixed  with  more  or  less  pus  in  the  cavity. 
The  disease  may  originate  from  a  catarrhal  condition  of  the 
lining  membrane  of  the  nasal  cavities;  chronic  alveolar  abscess  ; 
chronic  hyperplastic  diftiise  pericementitis;  or  cystic  formations. 
The  teeth  most  liable  to  cause  empyema  antri  are  the  second 
upper  bicuspids  and  the  first  molars ;  although  any  tooth  of  the 
upper  jaw,  by  protracted  purulent  inflammation,  may  induce 
the  disease.  While  an  alveolar  abscess  or  hyperplastic  perice- 
mentitis may  be  present  for  a  long  period  without  causing 
empyema  of  the  antrum,  sometimes  the  antrum  becomes 
affected  in  a  comparatively  short  space  of  time,  due  to  consti- 
tutional disturbances,  such  as  scrofula,    anaemia,    chronic   dis- 


EMPYEMA    OF    THE    AXTRUM.  543 

^ases  of  the  kidneys  or  the  liver,  tuherculosis,  etc.  In  many 
instances,  empyema  of  the  antrum  has  been  confounded  with 
cystic  formations  or  myxomata,  so-called  "  polypi,"' developed 
in  the  antrum,  or  its  immediate  vicinity.  Sometimes,  as  Zuck- 
erkandl  mentions,  cysts  fill  the  entire  cavity  of  the  antrum, 
and  simulate  the  symptoms  of  empyema  antri.  Such  cysts  have 
probably  been  the  cause  of  terming  the  disease  under  considera- 
tion "  hydrops  antri."  The  ailment,  therefore,  can  only  be 
called  "empyema  antri"  when  the  accumulated  secretion  is 
derived  from  the  lining  membrane.  In  this  condition  we  find 
the  mucous  membrane  of  the  antrum  considerably  swollen  and 
spongy.  The  communication  between  the  antrum  and  the  nasal 
cavity  ("  ostium  maxillare")  in  light  attacks  usually  is  pre- 
served, while  in  severe  cases  it  often  is  found  to  be  temporarily 
closed.  In  quite  chronic  cases,  however,  the  ostium  maxillare 
maybe  found  completely  obliterated ;  although  this  may  also 
occur  in  consequence  of  the  formation  of  polypi  in  the  hiatus 
semilunaris  (Zuekerkaudl).  When  the  ostium  maxillare  is 
closed,  the  facial  plate  of  the  antrum  becomes  more  or  less  ex- 
tended, often  causing  considerable  disfigurement  of  the  patient's 
face. 

Diagnosis. — The  principal  characteristic  of  empyema  antri  is  a 
catarrh  of  the  mucous  membrane  of  the  aifected  side  of  the  nose, 
accompanied  by  a  peculiar  disagreeable  odor.  The  nasal 
catarrh  is  quite  pronounced  if  the  ostium  maxillare  is  open, 
and  in  these  instances  the  accumulated  secretions  of  the  antrum 
flow  out  freely  when  the  patient  occupies  the  recumbent  posi- 
tion resting  upon  the  unaftected  side  of  the  face.  When  the 
ostium  maxillare  is  closed  the  face  shows  more  or  less  swellins:, 
and  the  facial  plate  of  the  afiected  antrum  easily  gives  way  upon 
pressure,  producing  the  peculiar  crepitation  similar  to  that  of 
parchment.  In  severe  cases  the  eye  protrudes  from  its  socket, 
and  the  nasal  cavity  becomes  obstructed  in  consequence  of  the 
bulging  of  the  nasal  wall  of  the  antrum.  A  characteristic 
feature  of  this  swelling  is  the  absence  of  fluctuation.  By  plac- 
ing the  index  finger  of  one  hand  on  the  palatine  surface  under 
the  antrum,  and  the  index  finger  of  the  other  hand  upon  the 
facial  portion  over  it,  by  alternating  pressure  we  are  sometimes 
enabled  to  produce  a  movement  of  the  contents  of  the  antrum. 
In  these  instances  the  bony  palatine  wall  of  the  antrum  has  like- 
wise been  absorbed,  and  crepitation  upon  pressure  is  present. 


544  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

Since  the  majority  of  antrum  troubles  are  caused  by  diseased 
teeth,  the  principal  attention  should  be  directed  to  the  examina- 
tion of  every  tooth  in  the  upper  jaw  of  the  atFected  side.  As  a 
rule,  the  offending  tooth  is  easily  detected  by  its  color,  as  well 
as  its  sound  upon  percussion,  because  such  teeth  invariably  are 
devitalized.  When  the  ostium  maxillare  is  closed,  we  some- 
times notice  a  slight  protrusion  of  the  second  bicuspid  and  first 
and  second  molars,  usually  outward,  although  the  teeth  may 
appear  comparatively  firm  in  their  sockets.  If  the  offending 
tooth  is  situated  under  the  antrum,  we  are  frequently  enabled  to 
obtain  entrance  to  the  antrum  through  the  pulp-canal  by  means 
of  a  fine  long  nerve-broach.  The  result  of  this  procedure  is  the 
evacuation  of  a  large  quantity  of  a  badly-smelling  fluid.  The 
gums,  though  more  or  less  inflamed,  seldom  show  fistulous 
openings,  unless  extensive  necrosis  be  associated  with  the  dis- 
ease under  consideration.  Transillumination  by  means  of  a 
small  electric  mouth-lamp  usually  yields  the  most  satisfactory 
results  in  the  diagnosis  of  empyema  of  the  antrum.  This 
method  enables  us  to  notice  the  slightest  hypertrophic  as  well  as 
catarrhal  condition  of  the  mucous  lining  of  the  antrum. 

Subjective  Phenomena. — In  the  incipient  stage  empyema  antri 
may  present  the  symptoms  of  acute  purulent  diffuse  pericemen- 
titis, and  cause  considerable  pain,  swelling  of  the  face,  and  fever, 
which,  however,  seldom  lasts  longer  than  from  two  to  three 
days.  This  is  followed  by  a  period  of  an  uneasy  sensation, 
though  the  tooth  has  remained  quite  sensitive  to  the  touch  ;  the 
pain  and  swelling  of  the  face,  as  well  as  the  general  symptoms 
of  fever,  mostly  having  abated.  The  patient  usually  becomes 
aflected  with  more  or  less  headache  and  earache,  and  sometimes 
with  more  or  less  neuralgia  of  the  affected  side  of  the  head. 
By  the  constant  discharge  of  foetid  pus,  either  through  the  nasal 
cavity  or  directly  into  the  mouth,  the  patient's  general  health 
becomes  noticeably  affected.  Sometimes  the  mucous  membrane 
of  the  nose  is  infected,  and  ulceration,  so-called  ozEena,  is  the 
result.  In  one  instance  the  author  has  observed  an  extensive 
eczema  of  the  affected  side  of  the  face  in  consequence  of  a 
severe  empyema  antri.  In  exceptional  cases  the  patient  notices 
a  clicking  sound  in  the  affected  antrum,  upon  turning  the  head 
from  one  side  to  the  other.  This  sound  is  said  to  be  similar  to 
that  produced  by  a  closed  bottle  half  filled  with  water,  when 
the  bottle  is  suddenly  inverted. 


EMPYEMA    OF    THE    ANTRUM.  545 

Differential  Diagnosis. — Empyema  of  the  antrum  may  easily  be 
confounded  with  ozBena  of  the  nose,  cysts,  or  polypoid  growths. 

Empyema  of  the  antrum  is  easily  differentiated  from  ozsena; 
as  in  the  latter  disease  the  catarrh  and  ulceration  are  present  in 
both  nasal  cavities,  while  in  empyema  antri  the  catarrh  only 
involves  one  side  of  the  nose.  TJni-  or  multilocular  cysts,  when 
located  in  the  alveolar  process  at  the  base  of  the  antrum,  are 
not  easily  diagnosed,  especially  when  they  are  large.  A  charac- 
teristic feature,  however,  of  a  large  cyst  developed  into  the 
antrum  is  that  the  inner  (nasal)  wall  of  the  antrum  seldom 
bulges  into  the  cavity  of  the  nose,  and  as  long  as  the  cyst  is 
intact  no  secretion  or  odor  can  be  noticed  in  the  corresponding 
nostril.  Furthermore,  the  walls  of  a  cyst  of  the  alveolar  pro- 
cess usually  are  hard  and  unyielding,  while  those  of  the  antrum 
affected  with  empyema  sometimes  are  yielding  to  pressure. 

When  a  cyst  occupies  the  cavity  of  the  antrum,  the  ostium 
maxillare  appears  closed,  unless  the  wall  of  the  cyst  becomes 
ruptured.  The  formation  of  a  cyst  in  the  antrum  always  is 
slow,  extending  over  a  period  of  many  months,  and  its  develop- 
ment never  is  accompanied  hy  fever  or  other  systemic  derange- 
ments. 

Myxomatous  tumors,  so-called  polypi  of  the  antrum,  accord- 
ing to  Zuckerkandl*  are  found  in  two  forms, — viz,  those  contain- 
ing glands,  and  others  without  them,  corresponding  to  the  irreg- 
ular distribution  of  glands  in  the  mncous  membrane  of  the 
antrum.  This  author  is  of  opinion  that  some  of  the  polypi 
containing  glands  degenerate  into  cysts  (Cysten-Polypen).  Such 
polypi  are  richly  supplied  with  blood-vessels,  and  upon  the 
slightest  injury  by  an  instrument  introduced  into  the  antrum 
bleed  profusely,  which  fact  is  characteristic  of  their  presence. 

The  prognosis  of  empyema  antri  largely  depends  upon  the 
general  constitution  of  the  patient,  which  when  good  will 
greatly  enhance  the  cure  of  the  disease.  Should  the  trouble  be 
caused  by  purulent  pericementitis,  the  tooth  must  be  sacrificed 
at  once.  In  most  of  these  instances,  however,  there  is  present, 
besides  the  empyema  of  the  antrum,  more  or  less  necrosis  of  the 
alveolar  process  or  jaw-bones,  which  must  be  removed  before 
the  mucous  membrane  of  the  antrum  can  be  successfully  treated. 
This  having  been  accomplished,  the  communication  between 
the  mouth  and  the  antrum  in  a  healthy  person  usually  obliter- 

*  "Die  Normale  und  Pathologische  Anatoinie  der  Nasenhohle."     Wien,  1892. 

36 


546  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

ates  \Yithin  one  to  four  Y^^eeks,  proYiding  that  the  mucous  mem- 
brane of  the  antrum  has  reached  a  normal  condition.  Empyema 
antri  in  consequence  of  an  infection  from  the  nasal  cavities,  in 
most  instances  abates  by  the  treatment  of  the  nasal  ca\Tity,  and 
does  not  strictly  belong  to  the  sphere  of  dentistry. 


CHAPTER   XLIV. 

THE  CLINICAL  AND  ANATOMICAL  FEATURES  OF  TUMORS  IN  GENERAL. 

Definition. — "WheneYcr  ne^Y  tissue  is  formed  at  the  surface  of 
the  body,  in  the  walls  of  its  cavity,  or  in  internal  organs,  we 
designate  it  as  a  tumor,  provided  the  augmented  bulk  of  tissue 
is  not  caused  by  inflammation.  The  best  definition  of  a  tumor 
ever  made  is  that  of  A.  Liicke,*  who  claims  that  an  inflam- 
matory new  formation  is  of  a  limited  course,  and  even  suppura- 
tion terminates  with  cicatrization ;  whereas  the  augmentation 
of  a  tissue  caused  by  a  tumor  has  no  physiological  termination, 
therefore  grows  indefinitely. 

Etiologi). — The  cause  of  the  growth  of  a  tumor,  as  a  rule,  is  a 
local  slight  irritation,  often  repeated  or  continuous.  In  previous 
years  the  term  "  disposition''  was  resorted  to,  to  explain  the 
appearance  of  tumors.  Obviously,  this  term  did  not  explain 
anything.  J.  Cohnheimf  established  the  theory  that  malignant 
tumors  always  originate  from  germs  misplaced  at  the  earliest 
period  of  development,  which  theory  has  proven  fallacious. 
The  celebrated  surgeon  Langenbeck,|  of  Berlin,  has  demon- 
strated that  so-called  gummy  tumors  of  the  tongue  often  become 
cancerous.  This  observation  alone  is  suflicient  to  overthrow 
Oohnheim's  theory.  In  many  instances  we  are  at  a  loss  to 
explain  the  origin  of  tumors.  It  is  always  the  safest  way  1o 
confess  ignorance  instead  of  promulgating  wrong  theories. 

Groicfh,  Benignity,  and  3Ialignity. — Although  the  properties  of 
the  tumors  concerning  their  innocuity  or  malignity  are  strictly 
of  a  clinical  value,  they  are  of  the  utmost  importance  to  the 
oral  surgeon,  in  order  to  ad^^Lse  his  patient  whether  a  tumor  is 

*  Chirurgie  von  Pitha  unci  Billroth.  Art.  Gescliwiilst. 

t  AUg.  Pathologie. 

%  Archiv.  f.  Klin.  Chirurrjle,  1875. 


CLIXICAL    AND    ANATOMICAL    FEATURES    OF    TUMORS.  547 

harmless,  not  endangering  life,  or  whether  the  removal  of  the 
tumor  is  an  absolute  necessity  to  preserve  life.  The  points  of 
differentiation  are  as  follows  : 

Pain. — Benign  tumors,  as  a  rule,  are  not  painful,  unless  ex- 
posed to  mechanical  injuries.  Cavernous  angioma  and  neuroma 
are  an  exception  to  this  rule,  since,  although  of  a  benign  type, 
they  are  painful  often  in  a  high  degree. 

DemarkatioiK — Benign  tumors  appear,  in  the  majority  of  cases, 
sharply  circumscribed  to  the  eye,  as  well  as  to  the  touch  v^dth 
the  point  of  a  finger.  Their  borders  are  easily  defined,  the 
tumors  often  being  inclosed  in  a  capsule,  which  renders  them 
movable.  Malignant  tumors,  on  the  contrary,  are  always  infil- 
trated, designating  that  they  lack  a  distinct  border,  but  difiusely 
blend  with  the  adjacent  tissues.  It  is  exceptional  that  a  malig- 
nant tumor  is  ensheathed  by  a  capsule  and  circumscribed  to  the 
touch. 

The  growth  is  not  always  decisive.  Some  benign  tumors, 
especially  if  inflamed,  may  grow  rapidly;  whereas  malignant 
tumors  may  exceptionally  make  slow  progress.  On  an  average, 
however,  it  is  true  that  benign  tumors  grow  slowly;  the  malig- 
nant ones,  on  the  contrary,  rapidly.  A  benign  fibroma  requires 
years  before  it  attains  a  conspicuous  size,  say  that  of  a  hazel- 
nut; while  a  sarcomatous  or  cancerous  tumor  may  reach  such  a 
size  within  one  year,  eventually  within  a  few  months. 

The  covering  skin  or  mucosa  will  remain  movable,  even  pliable, 
over  a  benign  tumor,  unless  inflammation  should  lead  to  its 
fixation.  Malignant  tumors  almost  invariably  soon  become 
infiltrated  into  the  tissues  of  the  skin  or  mucous  membrane, 
which  renders  them  immovable.  This  symptom  may  be  missing 
if  a  heavy  aponeurotic  layer  be  interposed  between  the  tumor 
and  the  surface. 

Reaction  upon  Adjacent  Tissues. — Benign  tumors,  growing 
slowly,  cause  no  irritation  or  inflammation  of  the  neighboring 
tissues,  especially  no  increase  in  the  size  of  the  adjacent  lymph- 
ganglia.  Malignant  tumors  always  cause  irritation  in  their 
environments,  and  especially  cancerous  tumors  will,  sooner  or 
later,  cause  a  swelling  of  the  lymph-ganglia  in  the  vicinity,  due 
to  an  invasion  of  the  lymphatics  with  cancer-epithelia  and  a 
transformation  of  the  lymph-  into  cancer-tissue.  Sarcomatous 
tumors  do  not  always  attack  the  lymph-ganglia,  though  they 
are  tumors  of  a  malignant  type. 


548  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

Ulceration  of  the  Surface. — Benign  tumors  will  ulcerate  only 
if  subjected  to  an  improper  treatment  with  caustics.  Other- 
wise it  is  a  rare  occurrence  for  benign  tumors  to  ulcerate  in 
consequence  of  their  weight  and  pressure  exerted  upon  the 
covering  skin  or  mucous  membrane.  Cancerous  tumors  invari- 
ably will  ulcerate  sooner  or  later,  owing  to  a  local  sloughing 
from  obliteration  of  blood-vessels.  Such  ulcers  are  crateriform, 
with  sharply-raised  borders,  of  an  uneven,  as  if  corroded,  base, 
lacking  granulations,  and  never  discharging  pus  copiously^ 
The  dried  pus  frequently  produces  a  crust  over  the  ulcer.  In 
such  cases  the  practitioner  should  beware  of  forcibly  removing 
the  crust  or  pressing  hard  upon  the  tumor.  A.  Gr.  Gerster  has 
shown  that  by  such  rough  treatment  cancer  elements  are  driven 
into  the  lymphatics,  thereby  causing  a  rapid  infiltration  of  the 
neighboring  lyraph-ganglia,  as  well  as  a  rapid  spreading  of 
the  disease.  Sarcomatous  tumors  likewise  may  ulcerate  on  the 
surface,  producing  smooth,  raw  surfaces,  discharging  but  little 
pus.  For  sarcoma,  however,  an  ulceration  is  not  the  rule,  as 
is  the  case  in  cancer. 

Infection  of  Remote  Tissues  and  Organs. — Benign  tumors  may 
be  present  in  large  numbers  over  the  surface  of  the  body,  or 
scattered  in  internal  organs.  They  will  never  cause  an  impair- 
ment of  the  general  constitution,  and  never  be  multiplied  by 
being  disseminated  through  the  blood  or  lymph-vessels.  Malig- 
nant tumors  will,  sooner  or  later,  debilitate  the  organism  and 
produce  secondary  tumors  of  their  own  kind  in  internal  organs, 
mainly  the  lungs,  the  liver,  and  the  kidneys ;  though  there  is 
no  organ  of  the  body  exempt  from  the  appearance  of  secondary 
deposits.  The  name  given  to  such  a  dissemination  of  malig- 
nant tumors  (sarcoftia  and  cancer)  is  "  metastasis."  To-day  we- 
know  that  it  is  a  carrying  away  of  particles  of  the  primary 
tumor  to  distant  organs,  especially  those  provided  with  a  narrow" 
capillary  net-work.  Here  the  dragged-ofF  particles  lodge  by  a 
process  called  embolism  and  thrombosis.  Wherever  particle& 
of  a  malignant  tumor  are  wedged  into  a  normal  tissue  or  organ,, 
a  new  tumor  will  be  produced  at  the  expense  of  the  surround- 
ing tissue,  which  is  directly  transformed  into  the  type  of  the 
tissue  of  the  tumor.  Sarcomatous  tumors  are  disseminated 
mainly  by  the  system  of  blood-vessels ;  cancer  tumors  mainly 
through  the  lymphatics.  Sometimes  the  last-named  tumors  are 
disseminated  through  the  lymphatics  in  a  retrograde  manner, — 


CLINICAL    A^^D    ANATOMICAL    FEATURES    OF    TUMORS.  549 

i.e.,  opposite  to  the  cnrrent  of  the  lymph.  The  secondary 
tumors,  in  the  majority  of  cases,  possess  the  properties  of  the 
original  one.  Exceptions  to  this  rule  are  cases  in  which  a 
rapidly-growing  cancer  causes  the  appearance  of  secondary 
nodules  in  the  lungs,  the  liver,  etc.,  with  all  characteristics  of 
sarcoma;  lacking,  therefore,  the  epithelial  structure  of  carci- 
noma altogether.  About  fifty  years  ago,  R.  Virchow*  already 
established  the  fact  that  intensely  malignant  and  rapidly-grow- 
ing cancers  change  into  sarcoma.  Later  researches  have  fully 
•corroborated  this  statement  of  the  great  German  pathologist. 

Diagnosis. — In  many  cases  of  tumors  the  recognition  of  their 
nature  is  not  difficult.  In  others  the  clinical  features  may  not 
be  so  pronounced  as  to  warrant  a  diagnosis.  In  such  cases  the 
microscope  is  called  upon  to  decide  dubious  questions,  provided 
that  the  microscopist  himself  is  an  experienced  and  conscientious 
observer.  A  wedge-shaped  piece,  the  size  of  a  pea,  is  cut  out 
of  the  tumor,  the  hemorrhage  being  checked  by  the  liquor 
sesquichloride  of  iron.  The  excised  piece  is  placed  into  a  fifty 
per  cent,  alcohol,  or,  preferably,  into  a  fifth  of  one  per  cent, 
solution  of  chromic  acid.  After  two  days'  hardening  the  tumor 
is  ready  for  examination  with  the  microscope,  first  being  sliced 
into  thin  slabs  by  means  of  a  razor. 

The  main  question  to  be  decided  by  the  microscope  is.  Is  the 
tumor  of  a  benign,  suspicious,  or  malignant  type?  Again,  in 
the  majority  of  instances,  the  microscope  is  able  to  give  a 
definite  answer  to  the  above  questions.  The  features  upon 
which  decision  is  possible  are  simple  enough.  The  more  basis- 
substance  is  present  between  the  protoplasmic  bodies,  the  so- 
called  cells,  the  more  certain  it  is  that  the  tumor  is  benign. 
The  more  crowded,  on  the  contrary,  the  protoplasmic  bodies, 
the  less,  therefore,  the  basis-substance,  the  more  certain  it  is  that 
we  have  to  deal  with  a  malignant  tumor.  In  the  worst  types  of 
malignant  tumors  the  basis-substance  is  completely  absent.  A 
mixture  of  these  two  features  will  render  the  tumor  suspicious, 
necessitating  an  early  extirpation. 

Even  a  well-versed  microscopist  may  meet,  exceptionally, 
with  difficulties  in  determining  the  nature  of  a  given  tumor. 
For  instance,  it  is  difficult  to  difierentiate  between  a  subacute 
inflammatory  process  of  the  fibrous  connective  tissue  and  a  fibro- 
sarcoma; the  latter  being  usually  diffuse,  the  former  scattered 

*  Archiv.f.  Path.  A?iat.,  1843. 


550  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

in  the  shape  of  inflammatory  nests.  It  is  impossible  to  dif- 
ferentiate between  the  tissue  of  a  syphilitic  gumma  and  a  highly 
malignant  lympho-sarcoma,  because  both  are  made  up  of  similar 
elements.  ]^either  the  clinician  nor  the  microscopist  alone 
should  rely  with  absolute  certainty  upon  their  findings.  Co- 
operation of  both  is,  as  a  rule,  necessary  to  reach  a  correct  final 
diagnosis. 

Prognosis. — A  tumor  of  the  benign  type  will  grow  slowly  and 
cause  disfigurement  of  or  discomfort  to  the  patient,  but  will  not 
endanger  his  life,  unless  vital  functions,  such  as  mastication, 
deglutition,  etc.,  be  interfered  with.  Eepeated  hemorrhages  may 
considerably  debilitate  the  constitution.  The  removal  of  such 
tumors  is  left  to  the  judgment  of  the  surgeon.  Quite  different 
is  it  with  suspicious  or  malignant  tumors,  the  removal  of  which 
is  an  urgent  necessity  on  account  of  the  dangers  involved  by  a 
rapid  local  growth,  by  ulceration,  by  repeated  hemorrhages, 
by  the  infiltration  of  neighboring  lymph-ganglia,  and  the  pro- 
duction of  secondary  tumors  in  distant  parts.  The  sooner  such 
tumors  be  removed,  the  better  are  the  chances  of  a  permanent 
cure.  Again,  the  question,  whether  or  not  a  tumor  is  operable, 
sometimes  is  left  altogether  to  the  judgment  of  the  surgeon. 

Classification. — C.  Heitzmann  in  1879*  issued  a  system  of 
classification  of  the  tumors,  entirely  based  upon  histological 
principles.  This  system  is  simple  and  comprehensible.  Accord- 
ing to  the  four  main  varieties  of  basis-substance  of  connective 
tissue,  the  myxomatous,  the  fibrous,  the  cartilaginous  or  chon- 
drogenous,  and  the  osseous,  he  arranges  the  benign  connective- 
tissue  tumors  proper  as  follows : 

1.  Myxoma  or  mucoid  tumor  (so-called  polypoid  tumors  of 
mucous  membranes). 

2.  Fibroma  ov  fibroid  tumor  (hard,  painless  tumors  to  be  found 
anywhere  in  the  connective  tissue). 

3.  Chondroma  or  cartilaginous  tumor  (hard,  smooth,  or  lobulated 
tumors  met  with  in  the  bony  system,  the  lungs,  etc.,  of  rare 
occurrence). 

4.  Osteoma  or  bony  tumor  (hard,  globular,  or  pointed  growths 
found  upon  the  skeleton ;  rare). 

The  embryonal  or  medullary  condition  of  the  connective 
tissue  furnishes  a  malignant  type  : 

5.  Myeloma  or  sarcoma.  The  term  "  sarcoma"  proposed  by  Vir- 

*  "Microscopical  Morphology."     New  York,  1883. 


CLINICAL    AND    ANATOMICAL    FEATURES    OF    TUMORS.  551 

chow  is  objectionable,  since  it  implies  a  fleshy  tumor  {oapy., 
flesh),  whereas  luyeloma  means  what  these  tumors  in  reality 
are, — i.e.,  medullary  tumors.  The  main  types  are  :  the  globo- 
myeloma  (round-celled  sarcoma  of  Virchow),  and  spindle  mi/eloma 
(spindle-celled  sarcoma  of  Virchow).  Such  tumors  are  of  a 
white  color,  the  so-called  encephaloid  of  old  authors,  or  more  or 
less  pigmented  melanotic  mytioina. 

The  combination  of  connective  tissue  with  fat,  with  a  large 
amount  of  blood-vessels,  with  smooth  muscles,  and  with  nerves, 
provides  four  other  benign  varieties  of  tumors: 

6.  Lipoma  ov  fatty  tumor  (common  in  the  subcutaneous,  rarer 
in  the  submucous  tissue). 

7.  Angioma  or  vascular  tumor. 

Such  tumors  consist  either  mainh'  of  newly-formed  blood- 
vessels, being  common  in  the  mucous  membrane  of  the  oral 
cavity,  or  of  newly-formed  lymphatics,  rarities  in  the  tissue  of 
the  skin. 

8.  Mponia  or  muscular  tumor  (most  common  in  the  walls  of 
the  uterus,  rarer  in  the  skin). 

9.  Nearoma  or  nerve  tumor  (rare,  exceedingly  painful  tumors, 
met  with  in  the  skin  and  the  central  nervous  organs). 

Any  one  of  these  eight  benign  tumors  may  combine  with  the 
type  of  myeloma  famishing  the  so-called  dubious,  or  suspicious 
tumors,  which  according  to  the  admixture  of  the  varieties  of 
connective  tissue  are  termed  myxo-myeloma,  fibro-myeloma, 
chondro-myeloma,  and  osteo-myeloma ;  according  to  the  amount 
of  fat,  blood-vessels,  smooth  muscles,  or  nerve-fibers,  lipo-mye- 
loma,  angio-myeloma,  myo-myeloma,  neuro-myeloma.  Such 
combinations  invariably  show  a  tendency  toward  malignancy, 
and  tumors  of  this  type  are  rather  prone  to  recur  after  extirpa- 
tion. 

The  combination  of  connective  with  epithelial  tissue  results 
in  the  production  of  two  varieties  of  benign  tumors : 

10.  Papilloma,  or  warty  tumor,  in  which  the  epithelium  fur- 
nishes the  outer  investment  of  the  tumor  (common  on  the  skin, 
comparatively  rare  on  mucous  membrane). 

11.  Adenoma,  or  glandular  tumor,  in  which  the  epithelia  pro- 
duce regular  glandular  formations  of  the  acinous  or  tubular 
variety,  often  combined  with  cysts. 

The  great  majority  of  cysts,  being  lined  at  the  inner  surface 
with  epithelia,  are  secondary  formations  of  adenoma.    Glandular 


552  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

tamers  may  be  built  up,  aside  from  the  epithelial  formations, 
of  myxomatous  or  fibrous  connective  tissue.  If  the  connective 
tissue  be  in  an  embryonal  or  medullary  condition,  we  speak  of 
an  adeno-myeloma.  This  combination  is  rare  in  comparison  with 
the  transformation  of  adenoma  into  carcinoma.  Cystic  cavities 
may  occur  in  any  of  the  benign  tumors,  but  not  being  lined 
with  epithelia,  should  not  be  termed  cysts  proper,  but  serous 
accumulations,  indicated  by  the  addition  of  the  word  hydro; 
such  as  hydro-myxoma,  hydro-fibroma,  etc.  (W.  Freudenthal.)* 
The  combination  of  connective  tissue  with  epithelium  inter- 
mixed in  the  shape  of  solid  nests,  plexuses,  pegs,  or  imperfect 
tubular,  gland-like  formations,  establishes  the  malignant  type 
of— 

12.  Carcinoma  or  cancer.  If  small  groups  of  epithelia  are  sur- 
rounded by,  and  intersected  with,  a  large  amount  of  dense, 
fibrous  connective  tissue,  this  form  is  termed  "  scirrhus."  If 
epithelial  pegs,  holding  concentrically  arranged  nests,  in  the 
centers  of  which  we  find  glossy  colloid  lumps  (so-called  "  cancer 
pearls"),  penetrate  into  the  connective  tissue,  we  speak  of 
"  dermoid  cancer'  or  "  epithelioma."  The  presence  of  tubular 
glands  means  the  adenomatous  preliminary  stage  of  carcinoma, 
which  form  is  dubbed  "  adenoid  cancer.''  If  epithelial  nests  are 
abundant,  lacking  regularity,  we  have  before  us  the  worst  type, 
— i.e.,  "  medullar}/  cancer."  The  connective  tissue  around  the 
epithelia  often  exhibits  glossy  corpuscles  of  the  size  and  aspect 
of  lymph-corpuscles.  The  more  numerous  such  corpuscles  the 
more  malignant  is  the  cancer,  and  the  more  rapidly  it  grows. 
Virchow  termed  this  feature  "  small  cellular  infiltration  ;"  Wal- 
deyer,  "  inflammatory  infiltration.'"  Heitzmann  has  proven  that 
the  corpuscles  under  consideration  present  the  earliest  stage  in 
the  development  of  cancer-cpithelia.  If,  after  extirpation  of  a 
cancer,  the  cut  surface  exhibits  such  corpuscles,  ever  so  few  in 
number,  we  can  with  certainty  expect  a  recurrence  of  the  cancer. 

*  "Two  Xasal  Polypi."     ArcJure.-i  of  Oplifludm.  and  Otology,  1893. 


TUMORS    OF    THE    TEETH. 


553 


CHAPTER  XLV. 


TUMORS    OF    THE  TEETH. 


The  majority  of  tumors  of  the  hard  tissues  of  the  teeth  are 
congenital.  All  of  them  are  of  a  benign  type,  and  either  sta- 
tionary or  of  an  extremely  slow  growth.  The  only  known 
tumor  of  the  pulp  is  malignant  myeloma. 

I.  Odontoma,  Tumor  of  the  Dentine. — Up  to  Virchow's  time 
€very  tumor  of  the  teeth  was    dubbed  odontoma.      Virchow 


Odontoma   of  a  Lower   Molar.    (From  Wedl.) 
Fig.  275. 


Odontoma.    Section  through  the  Thorny  Portion  of  Fig.  274.    (From  Wedl.) 

a,  a,  folds  of  enamel ;  h,  b,  layers  of  enamel ;  c,  central  space,  around  which  the  dentinal 
■canaliculi.are  arranged  in  a  radiating  manner.    Magnified  10  diameters. 

confined  this  term  to  tumors  of  the  dentine  only,  and  we  ought 
to  adhere  to  this  nomenclature.  Dentine  tumors  may  arise 
from  either  the  crown  or  the  root  in  the  shape  of  sessile  or 
pediculated,  smooth  or  lobate,  even  thorny  outgrowths.  (See 
I^ig.  274.)     If  sprung  from  the  dentine  of  the  crown,  they  are 


554 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


covered,  as  a  rule,  with  an  imperfect  enamel,  or  with  veetigeB 
of  formations  arising  from  the  root  portion;  such  appear 
coated  with  a  more  or  less  perfect  layer  of  cement.  Their 
structure  is  sometimes  similar  to  that  of  primary,  sometimes  to 
that  of  secondary,  dentine,  with  irregularly-distributed  groups 
of  dentinal  canaliculi.  In  rare  eases  the  dentinal  canaliculi  are 
arranged  radiatingly  around  spaces  carrying  blood-vessels,  so- 
called  vaso-dentine.     (See  Fig.  275.) 

Fig.  276. 


Teeth  with  Amelomata  oe  Enamel-Drops.    (From  Wedl.) 


^,  ameloma  on  posterior  surface  of  a  left  upper  molar;  B,a  right  upper  molar  with  four 
roots,  holding  an  ameloma  between  the  internal  roots  ;  C,  a  left  upper  molar  with  four  roots,^ 
holding  an  ameloma  between  the  two  posterior  roots. 

Fig.  277. 


Ameloma  or  Enamel-Dkop.    (From  Wedl.) 

^.stratified  enamel,  deeply  pigmented,  especially  toward  the  outer  surface;  i*,  dentinal 
cone,  with  irregularly-distributed  dentinal  canaliculi  and  interglobular  spaces.  Magnified  50 
diameters. 


II.  Ameloma,  Tumor  of  Enamel. — Formations  of  this  descrip- 
tion are  found  in  rare  instances  in  the  shape  of  white,  smooth 
nodules,  either  globular  or  oblong,  varying  from  the  size  of  a 


TUMORS    OF    THE    TEETH. 


555 


pin's  head  to  that  of  a  small  pea.  They  are  invariably  found 
at  the  beginning  of  the  bifurcation  of  the  roots  near  the  neck, 
and  are  often  connected  with  the  enamel  of  the  neck  by  means 
of  a  narrow  ridge.  (See  Fig.  276.)  In  malformed  or  dwarfed 
teeth  they  are  often  found  in  numbers  protruding  from  the 
ill-developed  crowns.  Their  structure  is  that  of  normal  enamel. 
At  their  base,  which,  as  a  rule,  is  broad,  is  seen  a  peg  of  normal 
dentine  penetrating  the  center  of  the  enamel-drop  to  a  varying 
distance.     (See  Fig.  277.) 

Fig.  279. 


Fig.  278. 


Osteoma  of  Neck  and  Root 
OF  A  Molar.    (From  Salter.) 


Osteoma  of  Neck  axd  Root  of  a  Molar. 
Vertical  Section.    ( From  Salter.) 

C,  layer  of  cementum  ;  D,  layer  of  dentine  ;  B,  bone-tissue, 
the  main  mass  of  the  tumor ;  /,  islands  of  dentine.  Magnified 
3  diameters. 


III.  Osteoma,  Bony  Tumor  of  the  Roots.— A  tumor  arising 
from  the  cementum  of  the  roots  is  termed  exostosis  if  circum- 
scribed, and  hyperostosis  if  diffuse.  Such  formations  are  prob- 
ably the  outcome  of  a  long-continued  irritation  of  the  cementum. 
(See  Chapter  XXX.)     In  rare  instances  tumors  of  considerable 


556 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


size  are  found  upon  the  roots,  composed  either  of  cancellous  or 
compact  bone-tissue  "with  islands  of  dentinal  tissue  interspersed. 
For  such  tumors  Salter  proposed  the  rather  awkward  term 
"  hernia."  (See  Fig.  278.)  Sometimes,  instead  of  regular  bone- 
tissue,  we  meet  with  globular  masses,  the  so-called  osteoid  tis- 
sue. Cancellous  bone  is  traversed  by  numerous  blood-vessels; 
compact  or  osteoid  tissue  is  scantily  supplied  Avith  them.  In 
Salter's  case  small  islands  of  dentine  were  found  in  the  middle 
of  the  newly -formed  bone-tissue.     (See  Fig.  279.) 

IV.    Gigantic   Growth,  or  Teratoma  of  Teeth. — This    term 
may  be  applied  to  extremely  rare  specimens  of  an  enormous 

Fig.  280. 


Gigantic  Growth  of  a  Right  Upper 
Molar.    Natural  Size.   (From  Wedl.) 


Gigantic  Growth  of  a  Right  Upper 
Molar.  Section  through  the  Inner 
and  between  the  two  outer  roots. 
Natural  Size.    (From  Wedl.) 


outgrowth  of  the  teeth,  especially  of  their  crowns,  in  which  all 
three  hard  tissues  of  the  tooth  are  involved.  They  may  also  be 
termed  "  teratoid,"  on  account  of  their  complicated  structure. 
The  best-studied  example  of  such  an  enormous  growth  is 
that  of  C.  Wedl,  of  the  illustrations  of  which  a  copy  is  herewith 
shown.     (See  Fig.  280,  A  and  B.) 

V.  Myeloma  of  the  Pulp. — This  form  of  malignant  tumor 
was  first  described  by  C.  Wedl.  Another  example  is  included 
in  my  own  collection.  Unfortunately,  in  neither  of  these 
instances  is  anything  known  concerning  the  history  of  the  pulps 
affected. 


TUMORS    OF    THE    TEETH. 


567 


In  both  cases  the  tumor  proved  under  the  microscope  to  be  a 
so-called  "  round-celled  sarcoma,"  or  as  I  would  prefer  to  term 
them,  "lympho-myeloma."  In  both  instances  the  tumors  had 
grown  in  largely-decayed  cavities  of  molars,  much  resembling 
the  appearance  of  a  granuloma  or  proud  flesh    of  the  pulp. 


Lympho-Mteloma  of  Pulp. 

S,  surface  made  up  of  blunt  papillary  elevations,  covered  with  a  single  layer  of  epithelia  ;  L, 
tissue  of  lympho-myeloma  ;  il/,  multinuclear  protoplasmic  body  :  C,  capillary  ;  T,  vein.  Mag- 
nified 50  diameters. 


With  low  powers  of  the  microscope  the  surface  appears  slightly 
lobated,  in  contradistinction  to  granuloma,  which  is  distinctly 
papillary  at  its  surface.  (See  Fig.  281.)  In  granuloma  the 
blood-vessels  are  abundant;  in  myeloma  scanty.     The  surface 


558 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


in  the  case  examined  was  found  to  be  covered  witli  partly 
stratified  epithelium,  the  same  as  in  the  case  of  granuloma 
described  in  the  chapter  on  "  Morbid  Anatomy  of  Pulpitis," 
page  403. 


Fig.  282. 


Lympho-Myeloma  of  Pulp. 

E,  columnar  epithelia  at  the  surface ;  M,  M,  tissue  of  lympho-myeloma,  with  scanty  spindles  ; 
G,  C,  capillary  blood-vessels.    Magnified  500  diameters. 


With  higher  powers  of  the  microscope  there  is  a  pronounced 
difterence  between  granuloma  and  myeloma,  (See  Fig.  282.) 
In  the  former  we  see  myxomatous  tissue  with  a  distinct  quantity 
of  basis-substance,   especially   in   the  deeper   portions   of  the 


CYSTS  IN  THE  ORAL  CAVITY.  559 

growth.  In  myeloma  only  vestiges  of  fibrous  connective  tissue 
can  be  seen,  but  no  myxomatous  basis-substance.  The  proto- 
plasmic bodies  are,  in  some  places,  crowded  together  to  such  a 
degree  that  they  flatten  one  another.  The  proportion  of  living 
matter  is  much  greater  in  the  tissue  of  myeloma  than  in  that  of 
granuloma. 

As  to  the  origin  of  the  covering  epithelia,  the  chapter  above 
referred  to  considers  the  two  possibilities  at  some  length. 


CHAPTER  XLVI. 

CYSTS  IN   THE   ORAL    CAVITY. 


From  a  histological  point  of  view,  only  those  tumors  with 
liquid  or  semi-solid  contents  in  which  the  connective-tissue  sac 
is  lined  on  its  inner  surface  by  epithelia  can  properly  be  called 
cysts.  The  best  opportunity  for  studying  genuine  cysts  is 
afforded  by  the  skin,  where  the  so-called  sebaceous  "  wens"  are 
of  frequent  occurrence.  We  know  that  every  one  of  these  cysts 
lias  an  adenomatous  preliminary  stage. 

In  a  certain  portion  of  the  acinous  sebaceous  glands  new 
formations  occur,  with  an  augmentation  of  the  epithelial 
structures,  after  which  the  gland  becomes  dilated,  and  fills  with 
either  a  fatty,  cream-like  sebaceous  mass,  or  a  jelly-like  liquid 
resembling  honey,  or  with  a  serous  liquid  rich  in  albumin. 
The  sebaceous  mass  which  primarily  filled  the  cyst  becomes 
transformed  by  secondary  changes  into  the  semi-liquid  or  liquid 
material. 

About  the  jaws  we  occasionally  meet  with  epithelial  growths 
originating  from  the  remnants  of  the  external  epithelium,  and 
the  epithelial  cord  of  the  former  enamel-organ,  to  which  Magitot 
was  the  first  to  draw  attention.  These  remnants  consist  of  flat 
epithelia,  arranged  in  concentric,  onion-like  nests,  which  may 
give  rise  to  epithelial  tumors  even  after  the  eruption  of  the  per- 
manent teeth.  Cases  have  been  observed  in  which  such  tumors 
formed  on  the  internal  surface  of  the  cheek,  of  hard  consistence, 
ulcerating  on  their  surface,  but  entirely  painless.    Upon  removal, 


560  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

a  number  of  epithelial  pearls  were  found  imbedded  in  newly- 
formed  connective  tissue.  (See  Fig.  283.)  Under  the  micro- 
scope these  pearls  can  only  be  interpreted  as  remnants  of  the 
external  epithelium  or  of  the  epithelial  cord  of  the  enamel- 
organ,  which  have  been  carried  awa}^  from  their  original  site 
into  the  mucous  membrane  of  the  cheek. 

Such  epithelial  formations  unquestionably  may  give  rise  to 
cysts,  which,  obviously,  will  be  lined  by  epithelia  and  develop 
without  symptoms  of  inflammation,  though  a  cyst  of  this  type 
may  become  inflamed  and  may  even  suppurate. 

Quite  different  is  the  source  of  cystic  tumors  around  the 
apices  of  the  teeth,  which,  clinically  as  well  as  microscopically, 
demonstrate  their  origin  from  an  inflammatory  process ;  prim- 
arily, an  accumulation  of  pus  in  a  so-called  alveolar  abscess. 
The  cavity  is  fllled  with  a  serous  liquid,  occasionally  slightly 
turbid  from  remnants  of  pus.  From  what  I  have  stated,  the 
term  cyst  is  not  properly  applied  to  instances  where  we  find  no 
epithelial  lining,  but  we  may  resort  to  this  term  if  we  call  them 
inflammatory  cysts. 

For  convenience'  sake  T  will  divide  the  cysts  occurring  in  the 
oral  cavity  into  two  classes, — viz  : 

I.  Cysts  arising  from  epithelial  tissue;  and 

II.  Inflammatory  cysts.  The  latter  develop  from  a  so-called 
pyogenic  membrane. 

I.  Epithelial  Cysts. — The  tumors  of  this  class  embrace  all 
growths  which  develop  either  from  glands  or  the  remnants  of  a 
former  enamel-organ,  which  are  enumerated  as  follows: 

1,  Ranula;  2,  Mucoid  Cysts;  3,  Dental  or  Dentigerous  Cysts; 
and  4,  Alveolar  Cysts. 

1.  JRanida. — This  term  has  been  applied  to  cystic  formations 
occurring  in  the  salivary  glands  on  the  floor  of  the  oral  cavity. 
Their  size  varies  considerably;  usually  it  is  that  of  a  hazel-nut, 
but  sometimes  the}^  attain  the  bulk  of  a  man's  fist.  Ranula 
always  grows  slowly,  and  when  large  it  may  become  an  impedi- 
ment to  speech,  mastication,  and  respiration.  It  is  sometimes 
translucent,  in  which  case  it  exhibits  a  thin  sac  filled  with 
liquid  or  semi-liquid  contents.  In  other  instances  it  is  opaque 
and  almost  solid,  which  is  due  to  a  thick  inclosing  wall  and 
semi-solid  contents,  consisting  mainly  of  epidermal  scales  in 
fatty  degeneration,  and  cholesterin  crystals.  The  origin  of  ran- 
ula is  as  yet  unsettled ;  the  most  commonly  accepted  theory 


CYSTS    IN    THE    ORAL    CAVITY. 


561 


\>emg  that  the  cyst  originates  by  a  dilatation  of  the  salivary 
gland.  This  theory,  however,  will  not  explain  the  appearance 
of  rannlfe  tilled  with  epidermal  scales.  The  latter  variety  prob- 
ably originates  from  the  so-called  gill-ducts,  which  are  present 
in  the  earliest  stages  of  embryonal  life. 

2.  Mucoid  Cysts. — These  tumors  are  of  rare  occurrence.  They 
appear  at  almost  any  part  of  the  oral  mncous  membrane  where 
there  are  mucous  glands,  but  usually  on  the  inner  surface  of  the 
cheeks  and  on  the  gums.     They  are  translucent,  bag-like  forma- 

Fm.  283. 


Epithelial  Globules  from  Scrapings  op  the  Inner  Cyst-AVall  of  the 
Right  Cheek. 

G,  G,  globules  made  up  of  concentrically-arranged  epithelia;  F,  shreds  of  fibrous  connective 
tissue.    Magnified  500  diameters. 


tions,  never  larger  than  a  pea  in  size,  are  superficially  imbedded 
in  the  mucous  membrane,  and  easily  movable  in  all  directions. 
They  probably  originate  from  adenomata  of  the  mucous  glands 
of  the  oral  cavity.  Their  contents  are  usually  of  a  liquid  or  a 
mucoid  consistence. 

3.  Dental  or  Bentigerous  Cysts. — According  to  John  Tomes,* 
the  term  "  dentigerous  cyst"  is  limited  to  cysts  which  arise  in 
connection  with  developing  teeth,  or  teeth  which,  though  their 
development  has  been  completed,  are  retained  within  the  sub- 

*  "A  System  of  Dental  Siirgery,"  1873. 
37 


562 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


stance  of  the  jaw.  In  the  majority  of  cases  they  are  connected 
with  permanent  teeth,  and  in  some  instances  with  supernumer- 
ary teeth.  This  author  describes  a  remarkable  cyst  which  con- 
tained twenty-eight  supernumerary  teeth.  The  patient  stated 
that  on  the  right  side  of  the  upper  jaw  the  cuspid,  bicuspids, 
and  first  molar  had  failed  to  make  their  appearance.  At  the 
age  of  twelve  a  hard,  painless  swelling  appeared  on  that  side  of 
the  jaw,  which  subsequently  became  inflamed  and  painful ;  at  the 
same  time  pus  oozed  out  in  large  quantities  around  the  root  of 
a  temporary  molar  which  had  been  retained.  The  twenty-eight 
teeth  were  dwarfed,  and  of  very  irregular  form,  one  having  no 
less  than  nine  cusps.     (See  Fig.  284.) 

Fig.  284. 


^     ^ 


Dtvaefed  and   Malformed  Teeth  out  of  a  Dextigeeous  Cyst  op  the  Right  Side  of 
THE  Upper  Jaw.    (From  John  and  Charles  S.  Tomes.) 


Another  instance  of  a  dentigerous  cyst  is  described  by  John 
Tomes  in  a  patient  aged  twenty-five,  who  presented  with  a 
large  tumor  in  the  front  of  the  upper  jaw,  the  surface  of  which 
was  eroded  by  ulcers  and  profusely  discharging  offensive  pus. 
Fifteen  ill-developed,  partly  hyperplastic,  and  gigantic  teeth 
were  extracted,  and  probably  a  few  more  had  been  lost  in  the 
operation.  The  teeth  absent  from  the  mouth  were  the  central 
and  lateral  incisors,  the  cuspids  occupying  their  usual  position. 

J.  Tomes  states  that  cysts  arising  in  connection  with  teeth 
retained  in  the  jaw  do  not  always  contain  a  number  of  super- 
numerary teeth  ;  often  only  a  single  tooth,  commonly  belong- 
ing to  the  permanent  set,  is  found,  though  cases  are  recorded. 
of  cysts  arising  in  connection  with  temporary  teeth.  In  some 
cases  bony  walls  develop  around  the  cyst.     Tumors  of  this  type 


CYSTS    IX    THE    ORAL    CAVITY. 


563 


may  attain  to  an  enormous  size,  but  they  are  very  rare.  Fig. 
285  represents  the  bony  wall  of  a  dentigerous  cyst,  from  a  case 
in  which  Lisfranc  had  extirpated  the  affected  half  of  the  jaw. 


FiCx.  285. 


Dextigerous  Cyst  involving  the  Body  and  the  Ramus  of  the  Right  Half  of  the 
Inferior  Maxilla.    (From  Forget.) 

M,  inverted  third  molar  ;   /,  inferior  dental  canal ;    C,  internal  wall  of  the  cyst. 

John  and  Charles  S.  Tomes  remark  that,  had  a  correct  diagnosis 
been  made,  a  much  milder  procedure  would  have  led  to  a  cure. 
Fig.  286  represents  three  teeth  of  the  upper  jaw  found  in  a 
cyst  by  Dr.  M.  H.  Cryer,  of  Pbiladelphia,  and  kindly  offered  to 
me  for  illustration. 

Fig.  286. 


Right  Upper  Incisors  and   Cuspid   found  in  a  Cystic   Cavity. 

» 

4.  Alveolar  Cysts. — In  this  group  I  propose  to  locate  all 
cysts  of  undoubted  epithelial  origin,  but  not  depending  upon 
retained  teeth.  The  case  of  which  illustrations  are  attached 
was  that  of  a  man,  about  fifty  years  of  age.     The  cyst,  of  the  size 


564 


THE  ANATOMY  AND  PATHOLOGY  OF  THE  TEETH. 


of  a  bazel-nnt,  was  situated  at  the  site  of  the  left  lower  first 
molar,  which  was  extracted  some  fifteen  years  ago.  The  wall 
of  the  cj'st  presented  the  appearance  illustrated  in  Fig.  287. 
The  inner  surface  was  studded  with  papillae  covered  by  epithe- 
lia,  the  whole  appearing  lobulated.  The  lobules,  two  of  which 
are  seen  in  the  figure,  consist  of  bundles  of  fibrous  connective 
tissue,  freely  supplied  with  capillary  and  venous  blood-vessels, 
the  connective  tissue  being,  in  many  places,  crowded  with  in- 
flammatory corpuscles. 

Fig.  287. 


Papillary  Vegetations  at  the  Ixner  Surface  of  Cyst-Wall. 

A  ,  B,  vegetations  crowded  with  papilla  ;  E,  E,  stratified  epithelium  covering  the  papillse. 
Magnified  50  diameters. 


With  higher  power  of  the  microscope,  the  epithelium  cover- 
ing the  papillae  proved  to  be  indistinctly  stratified.  (See  Fig.  288.) 

II.  Inflammatory  Cysts. — The  origin  of  inflammatory  cysts 
is,  in  the  majority  of  cases,  as  follows : 

The  pulp  of  a  tooth  becomes  devitalized,  causing  an  alveolar 
abscess,  whereby  a  portion  of  the  adjacent  cancellous  bone- 
tissue  of  the  socket  is  destroyed.     The  pus  makes  its  way  to 


CYSTS  IX  THE  ORAL  CAVITY. 


565 


the  surface  of  the  alveolar  process,  which  is  covered  with  rem- 
nants of  the  periosteum  or  only  with  mucous  membrane.  The 
suppuration  comes  to  a  standstill,  and  the  abscess  is  what  the 
surgeons   usually    call   encysted.     In    turn,   the  pus-corpuscles 


EiG.  288. 


7Ry 


Papillary  Vegetations  at  the  Ixxer  Surface  of  Otst-Wall. 

P,  P,  papillaj  made  up  of  fibrous  connective  tissue,  with  numerous  capillary  blood-vessels  ; 
7,  inflammatory  infiltration  of  fibrous  connective  tissue  ;  E.  E,  stratified  epithelium  covering 
the  papillae.    Magnified  500  diameters. 


either  creep  back  into  the  lymphatics  and  are  carried  away,  or 
they  become  hydropic  and  are  destroyed.  If  mucous  membrane 
is  the  only  outer  covering  of  the  sac,  it  usually  bulges  into  the 
oral   cavity  in   the  shape  of  a  tense,  elastic  tumor,  exhibiting 


566  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

fluctuation,  but  lacking  symptoms  of  inflammation.  Should 
the  wall  of  the  sac  hold  remnants  of  periosteal  tissue  that  have 
escaped  destruction,  it  "will  give  rise  to  a  new  formation  of  bone, 
which,  in  turn,  may  envelop  the  sac  with-  an  osseous  wall.  Since 
such  a  newly-formed  bony  wall  is,  as  a  rule,  thin  and  imperfect, 
the  tumor  will  remain  elastic  and  compressible. 

A  noteworthy  fact  about  these  inflammatory  cj-sts  is  that 
tl'iey  occur  only  in  persons  of  a  poor  constitution,  in  whom  the 
inflammatory  process  advances  but  slowly.  The  pus  in  these 
instances  is  rather  serous,  containing  but  a  limited  number  of 
pus-corpuscles  that  are  easily  liquefied. 

The  diagnosis  of  alveolar  cysts  is  usually  not  difficult.  Such 
cysts  are  met  with  more  frequently  in  the  upper  than  in  the 
lower  jaw,  and  they  are  mostly  situated  in  the  outer  wall  of  the 
alveolar  process.  They  are  found  more  frequently  upon  the  in- 
cisors and  bicuspids  than  the  molar  teeth,  and  very  seldom  near 
the  roots  of  the  cuspids.  When  a  cyst  develops  in  the  neigh- 
borhood of  the  antrum,  it  may  lead  to  an  incorrect  diagnosis. 
In  these  instances  the  cy&i  may  bulge  into  the  antrum,  pressing 
its  floor  upward,  thus  occupying  almost  the  entire  cavity.  In 
such  a  case  the  cyst  may  be  mistaken  for  empyema  of  the  antrum, 
especially  if  the  offending  tooth  or  root  has  been  removed  some 
time  previous.  The  wall  separating  the  cyst  from  the  antrum 
is  usually  left  intact,  and  the  communication  between  the  antrum 
and  the  nasal  cavity  is  cut  off".  Another  important  fact  in  the 
diagnosis  of  alveolar  cysts  is  the  absence  of  catarrhal  inflamma- 
tion in  the  nasal  passage  on  the  affected  side,  which,  in  an  empy- 
emic  condition  of  the  antrum,  always  is  or  has  been  present. 
We  also  have  to  take  into  consideration  the  size  of  the  cyst.  If 
this  be  large  and  occupying  almost  the  whole  of  the  antrum,  the 
wall  common  to  both  the  antrum  and  the  cyst  may  become 
perforated,  and  a  discharge  of  the  contents  of  the  cyst  into  the 
nasal  cavity  be  the  result.  Wlien  the  outer  bony  wall  of  a  cyst 
is  thin,  the  tumor  will  be  compressible,  with  the  sensation  of 
crepitation.  The  growth  of  a  cyst  usually  is  slow.  In  the  first 
stages,  and  so  long  as  no  acute  inflammation  occurs,  the  patient 
experiences  no  pain,  nor  inconvenience.  When,  however,  the 
sac  begins  to  assume  greater  dimensions,  the  patient  may  be 
.  troubled  by  headaches  as  well  as  a  disturbance  of  the  eyesight, 
more  or  less  conflned  to  the  aflfected  side.  Pressure  with  the 
finger  produces  no  pain,  unless  the  tumor  has  become  large  and 


CYSTS  IX  THE  ORAL  CAVITY.  567 

tense.  In  the  advanced  stages  slight  percussion  upon  the 
tooth  from  which  the  cyst  originated  is  painless,  and  the  tooth 
itself  is  usually  lirm  in  its  socket. 

The  prognosis  of  cystic  tumors  is  generally  favorable,  except 
in  those  rare  instances  when  a  perforation  of  the  wall  of  the 
antrum  has  taken  place.  The  complete  removal  of  the  sac  or  a 
portion  of  it  will  usually  prevent  recurrence. 

When  a  cyst  develops  around  the  root  of  an  incisor  tooth 
without  the  root  being  absorbed  by  the  inflammatory  process, 
the  removal  of  the  tooth  is  not  absolutely  necessary.  If  the 
root-canal  of  an  otherwise  normal  tooth  with  but  one  root  be 
thoroughly  disinfected  and  filled,  it  may  be  left  in  the  mouth 
without  fear  of  recurrence  of  the  cyst. 

The  microscopical  study  of  specimens  from  the  wall  of  the 
cyst  is  of  considerable  interest,  since  it  ofiiers  an  opportunity  to 
trace  both  the  destructive  and  formative  actions  of  the  inflam- 
matory process. 

Transverse  sections  through  the  wall  of  the  cyst  exhibit  the 
following.     (See  Fig.  289.) 

The  outermost  layer  is  established  by  the  unbroken  gum, 
partly  normal  and  partly  changed  by  chronic  ulitis.  The  papillae 
in  the  latter  places  are  irregular  in  size  and  shape,  the  border 
toward  the  epithelial  covering  being  rather  indistinct.  The 
connective-tissue  layer  of  the  gum  exhibits  dilated  blood-ves- 
sels. ISText  follows  the  periosteum  of  the  socket,  composed  of 
coarse  interlacing  bundles  of  fibrous  connective  tissue,  with 
numerous  inflammatory  nests.  The  most  pronounced  inflam- 
matory changes  are  observed  along  the  border  of  the  cancellous 
bone-tissue.  The  bony  wall  of  the  alveolus  is  considerably  re- 
duced in  bulk,  being  pierced  by  numerous  bay-like  excavations 
filled  with  medullary  or  myxomatous  tissue.  Where  the  outer 
lamellated  layer  of  the  socket  is  still  preserved,  the  cancellous 
bone-tissue  has  been  reduced  by  the  inflammatory  process  to 
scanty  and  irregular  spiculse  of  bone-tissue.  These  are  in  con- 
nection with  the  outer  wall  of  the  socket,  or  apparently  isolated 
by  a  newly-formed  myxo-fibrous  connective  tissue  which  forms 
the  wall  of  the  cyst.  This  tissue  again  holds  spiculse  of  newly- 
formed  bone.  The  specimens  in  man}^  places  are  crowded  with 
red  blood-corpuscles,  so-called  hemorrhagic  infarctions,  which, 
judging  from  the  fresh  appearance  of  the  red  blood-corpuscles, 
must  have  been  produced  by  extravasation  during  the  removal 


568 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH, 


of  the  wall  of  the  cyst.  The  contents  of  the  cyst  are  made  up 
of  coagulated  albumin  and  red  blood-corpuscles.  No  vestige  of 
previous  pus-corpuscles  can  be  detected. 


Fig.  289. 


Wall  of  an  Inflammatory  Cyst  ix  Transverse  Section. 

G,  G,  stratified  epithelium  of  gum ;  N,  partly  normal,  partly  inflamed  papillae  of  gum;  P, 
periosteum  with  inflammatory  nests  ;  A,  A,  wall  of  alveolus,  much  reduced  by  osteitis  ;  W,  W, 
myxo-fibrous  tissue-wall  of  cyst,  partly  in  hsemorrhagic  infarctus ;  B,  newly-formed  spicula  of 
bone-tisSue  ;  (7,  contents  of  cyst.    Magnified  25  diameters. 

The  layers  adjacent  to  the  tissue  of  the  gum  are  the  periosteum 
and  the  bone,  both  considerably  altered  by  the  inflammation, 
as  represented  in  Fig.  290. 

The  fibrous  tissue  of  the  periosteum  holds  numerous  inflam- 
matory nests.     They  consist  of  granu]a;r  protoplasmic  bodies 


CYSTS    IX    THE    ORAL    CAVITY. 


569 


which  had  not  developed  into  new  fibrous  connective  tissue. 
At  its  surface  the  bone-tissue  is  marked  by  numerous  excava- 
tions varying  in  depth,  and  filled  with  multinuclear  protoplasmic 


Fig.  290. 


'G'  ^^ ' 


Periostitis  axd  Osteitis. 

L,  longitudinal  bundles  of  periosteum  ;  T,  transverse  bundles  of  periosteum  ;  N,  N,  inflam- 
matory nests  ;  M,  myso-iibrous  connective  tissue  ;  P,  multinuclear  protoplasmic  bodies  filling 
the  bays  of  bone-tissue  ;  0,  0.  osteitis,  enlarged  and  confluent  bone-corpuseles  :  S,  S,  medullary 
spaces  of  inflamed  bone-tissue,  filled  with  myxo-fibrous  tissue  ;  C,  calcified  rim  around  medul- 
lary space.    Magnified  200  diameters. 


bodies,  or  myeloplaxes.  The  bone  is  honeycombed  with 
medullary  spaces  that  are  filled  partly  with  myxo-fibrous  tissue, 
resembling  that  of  the  cyst-wall  proper. 


570 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


The  changes  iu  the  inflamed  boue-tissue  are  still  more  con- 
spicuous  if  examined  with  higher  powers.     (See  Fig.  291.) 

Here  we  observe  bone-corpuscles  of  greatly  varying  sizes. 
The  smallest  are  scarcely  as  large  as  normal  ones,  so  that  we 


Fig.  291. 


Osteitis  and   Myxo-Fibrous  Tissue   of  Cyst-Wall. 

*  T,  T,  trabeeulae  of  bone,  much  reduced  by  osteitis  ;  fi,  bone-corpuscles,  slightly  enlarged  ;  G^, 
bone-corpuscles,  much  enlarged;  C^,  bone-corpu?cles,  transformed  into  a  medullary  space;  M, 
myxo-fibrous  connective  tissue  ;  jT  (right  upper),  capillary  blood-vessel  in  transverse  section; 
L,  capillary  blood-vessel  in  longitudinal  section.    Magnified  500  diameters. 

may  consider  them  as  former  ofishoots,  so-called  canaliculi, 
which  have  been  enlarged  by  the  liquefaction  of  the  decalcified 
glue-yielding  basis-substance.  Other  bone-corpuscles  are  not 
materially  altered  in  size,  but  different  from  normal  ones  by  a 


CYSTS    IN    THE    ORAL    CAVITY.  571 

coarse  granulation  of  their  protoplasm.  Many,  however, 
have  become  augmented  in  size  to  such  a  degree  that  they  have 
reached  the  diameter  of  Haversian  canals.  All  these  enlarged 
bone-corpuscles  hold,  besides  coarse  granules,  a  varying  number 
of  homogeneous  lumps,  some  reaching  the  size  of  nuclei.  By 
a  coniiuence  of  such  enlarged  bone-corpuscles  we  observe  the 
origin  of  medullary  spaces  in  the  bone,  independent  of  pre- 
vious medullary  spaces  or  Haversian  canals. 

The  cyst-wall  proper  is  altogether  made  up  of  a  myxomatous 
and  myxo-fibrous  connective  tissue,  only  scantily  supplied  with 
capillary  blood-vessels.  Thirty  years  ago  this  tissue  was  not 
recognized  by  E.  Virchow,  who  claimed  that  the  layer  bordering 
upon  a  pus-cavity  was  unfinished  pus,  which  he  termed  "pus 
crudum."  That  this  view  is  not  correct  is  proved  not  only  by 
my  specimens,  but  also  by  the  study  of  L.  Heitzmann  on 
"Abscesses  in  the  Skin"  {Arch.  f.  Dermatol,  1892). 

The  myxomatous  tissue  is  composed  of  branching  tracts  of  a 
delicate  fibrous  reticulum,  at  the  points  of  intersection  of  which 
we  see  so-called  branching  stellate  protoplasmic  bodies.  The 
fields  of  basis-substance  are  likewise  of  a  delicate  reticular 
structure,  and  contain  small  homogeneous  or  coarsely-granular 
bodies,  about  the  size  of  lymph-corpuscles.  It  can  scarcely  be 
doubted  that  this  newly-formed  tissue,  the  like  of  which  is  never 
observed  in  normal  bone  or  periosteum,  is  the  outcome  of  an 
inflammatory  or  medullary  tissue,  into  which  both  the  bone  and 
the  periosteum  have  been  transformed  by  the  process  of  inflam- 
mation. 

In  the  myxo-fibrous  cyst-wall  we  frequently  meet  with  depo- 
sitions of  lime-salts,  as  well  as  newly-formed  spiculse  of  bone- 
tissue.     (See  Fig.  292.) 

The  trabeculse  of  this  newly-formed  bone  in  the  wall  of  the 
cyst  are  but  few  and  small  in  size.  We  notice  in  their  vicinity 
deposits  of  lime-salts  without  any  indication  of  bony  new  for- 
mation. The  only  feature  indicative  of  future  bone  is  the 
presence  of  calcified  medullary  corpuscles,  arisen  from  the 
myxomatous  tissue.  The  next  step  toward  the  formation  of  bone 
is  the  appearance  of  territories.  By  the  coalescence  of  a  number 
of  territories  a  spicala  of  bone-tissue  will  be  formed,  which 
invariably  shows  at  its  periphery  more  or  less  perfect  rows  of 
medullary  corpuscles,  the  so-called  "  osteoblasts."  A  second 
characteristic  feature    of  the  newly-formed  bone-tissue  is  the 


572 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


large  size  aucl  great  irregularity  in  the  shape  of  the  bone-cor- 
puscles, the  oifshoots  of  which  are  unusually  well  pronounced. 
The  third  feature  is  the  absence  of  lamellae.     Such  bony  spiculse 


Fig.  292. 


Xewlt-Formed   Spicula  of    Boxe-Tissue  in   Ctst-Wall. 

5.  spicula  of  bone,  traversed  bj' medullary  spaces:  0,  row  of  osteoblasts  ;  T,  territory  of 
bone-tissue ;  3f,  myxo-fibrous  tissue  of  cyst-wall ;  L,  capillary  blood-vessel  in  longitudinal 
section  ;  C,  capillary  blood-vessel  in  transverse  section  ;  M,  lijemorrhagie  infarctus.  Magnified 
500  diameters. 


are  found  imbedded  in  fibrous  or  myxo-fibrous  connective  tissue, 
but  never  in  a  purely  myxomatous  one. 


TUMORS    OF    THE    JAWS.  573 

CHAPTER    XLVIL 

TUMORS  OF  THE  JAWS.* 

I.  Myxoma. — This  variety  of  tumor  is  not  rare  on  the  gums 
around  the  teeth.  The  specimen  under  observation  is  the  size 
of  a  robin's  egg,  with  a  nodulated  surface,  originally  of  a  blood- 
red  color,  of  rather  soft  consistence,  and  grown  upon  the  gum 
of  the  lower  jaw,  left  side  between  the  second  bicuspid  and  first 
molar.  It  had  recurred  at  every  pregnancy,  this  being  the  third, 
in  the  mouth  of  a  lady  aged  about  twenty-six  years.  Tumors 
had  been  removed  from  the  same  locality  four  ditterent  times, 
when  the  patient  was  a  girl  from  twelve  to  fourteen  years  of  age. 

With  low  powers  of  the  microscope  the  raspberry  or  papillary 
appearance  was  well  marked  upon  the  surface,  as  represented 
in  Fis;.  293.  The  surface  is  coated  with  a  sino;le  row  of  colum- 
nar  epithelium,  without  distinct  boundary  toward  the  subjacent 
connective  tissue,  the  lowest  portions  of  columnar  epithelia  and 
the  bodies  wedged  in  between  them  blending  with  the  adjacent 
layers  of  medullary  tissue.  The  so-called  structureless  layer 
can  be  made  out  in  but  few  places.  The  main  mass  of  the 
growth  consists  of  an  extremely  delicate  net- work  of  fibrous 
connective  tissue  with  interspersed  nuclei  mainly  at  the  points 
of  intersection.  The  meshes  of  this  net-work  contain  as  a  rule 
only  one  medullary  corpuscle ;  but  near  the  surface  the  cor- 
puscles are  present  in  large  numbers,  to  such  an  extent  that  the 
reticulum  is  rendered  invisible.  The  corpuscles  are  compara- 
tively small  and  nearly  compact  near  the  periphery,  while  they 
are.  granular  and  markedly  larger  in  the  deeper  portions.  The 
outermost  portions  of  the  tumor,  owing  to  the  abundance  of 
medullary  corpuscles,  have  the  character  of  a  myeloma;  but 
the  gradual  appearance  of  a  myxomatous  basis-substance  in  the 
deeper  portions  proves  that  the  tissue  is  myxomatous,  and  the 
clusters  of  the  medullary  corpuscles  merely  signify  a  rapid 
growth  at  the  surface. 

A  striking  feature  of  this  growth  is  the  large  number  of  wide 
capillary  blood-vessels,  which  run  mainly  in  a  vertical  direction 
to  the  surface,  and  therefore  appear  in  transverse  sections  where 

*The  greater  portion  of  this  chapter  has  been  taken  from  an  article,  "  Contri- 
butions to  the  Knowledge  of  Tumors  of  the  Jaws,"  by  Carl  Heitzmann  and 
Frank  Abbott.     Dental  Cosmos,  1888. 


574 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


Fig.  293. 


Myxoma  or  Granuloma  of  the  Gum  of  the  Lower  Jaw. 


L,  longitudinal ;   T,  transverse  section  of  the  papillae  on  the  surface  ;  M,  myxomatous  tissue ; 
V,  blood-vessels  traversing  the  myxomatous  tissue.    Magnified  200  diameters. 


TUMORS    OF    THE    JAWS.  575 

the  papillae  are  cut  transversely.  The  arrangement  of  the  capil- 
laries in  a  tassel-like  manner  seems  to  account  for  the  papillary 
or  nodular  architecture  of  the  surface.  The  so-called  proud- 
flesh  or  granulation-tissue  of  suppurating  wounds  has  the  same 
structure  as  the  tumor  under  consideration,  and  some  authors 
speak  of  a  granuloma  corresponding  to  the  structure  of  a  myx- 
oma, but  being  a  product  of  an  inflammator}'-  process.  In  the 
deeper  portions  of  the  tumor  delicate  bundles  of  fibrous  connec- 
tive tissue  are  visible,  and  most  of  the  vessels  are  accompanied 
by  tracts  of  such  tissue,  by  which  an  adventitial  coat  is  produced, 
even  around  the  capillaries,  which  is  not  visible  in  normal  tissue. 
In  the  deepest  portions  the  fibrous  connective  tissue  is  rather 
abundant,  the  medullary  corpuscles  being  at  the  same  time 
scanty,  and  the  blood-vessels  bearing  the  character  of  veins. 

II.  Myxo-Fibroma. — This  variety  of  benign  tumors  is  likewise 
known  as  occurring  frequently,  taking  issue  both  from  the  gums 
and  the  periosteum.  Its  consistence  is  harder  than  that  of  a  pure 
myxoma,  and  softer  than  that  of  a  pure  fibroma.     (See  Fig.  294.) 

The  illustration  is  taken  from  the  deepest  portions  of  the 
myxoma  above  described.  It  consists  of  interlacing  bundles  ot 
a  delicate  fibrous  connective  tissue,  exliibiting  therefore  an  in- 
distinct reticular  arrangement.  The  meshes  between  the  bun- 
dles are  filled  with  a  finely-granular  basis-substance,  in  which 
medullary  corpuscles  are  stored  up  in  varying  numbers.  The 
blood-vessels  are  comparatively  scanty,  consisting  of  capillaries 
and  veins,  all  of  which  are  surrounded  by  a  distinct  layer  of 
fibrous  connective  tissue.  The  endothelia  of  the  capillaries  are 
unusually  large  and  bulging  toward  the  channel.  In  some  places 
the  capillary  appears  to  be  surrounded  by  two  or  more  endo- 
thelial layers,  which  add  considerably  to  the  thickness  of  the 
vascular  wall.  The  specimen  aftbrds  a  good  opportunity  for  the 
study  of  the  manner  in  which,  first,  myxomatous  arises  from 
medullary,  and  fibrous  from  myxomatous  tissue,  a  process  which, 
as  is  well  known,  is  of  frequent  occurrence  in  the  history  of  de- 
velopment of  normal  fibrous  connective  tissue.  At  first  the 
tissue  is  apparently  nothing  but  an  aggregation  of  indifferent  or 
medullary  corpuscles,  the  tissue  nature  of  which  is  determined 
only  by  the  fact  that  all  the  corpuscles  are  united  with  one  an- 
other by  means  of  delicate  threads.  The  corpuscles  themselves 
are  originally  small  homogeneous  lumps,  of  a  high  degree  of 
refraction.     Soon  afterward  a  number  of  such  indifferent  cor- 


576 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


puscles  assume  a  granular  appearance,  and  between  them  an 
extremely  delicate  reticulum  appears  as  the  first  trace  of  a  reticu- 
lar structure.     At  this  stage  of  development,  which  we  often  see 


Fig.  294. 


Myxo-Fibroma  of  the  Gum  of  the  Lower  Jaw. 

M,  myxomatous  tissue,  composed  of  delicate  fibrous  bundles ;  -M^,  the  bundles  coarser  still, 
exhibiting  the  reticular  arrangement ;  LP,  the  fibrous  bundles,  broad,  inclosing  fields  of  a 
myxomatous  basis-substance  ;  F,  F,  large  capillary  blood-vessels.    Magnified  500  diameters. 


TUMORS    OF    THE    JAWS.  577 

in  inflamed  tissue,  some  authors  have  spoken  of  an  adenoid  or 
lymph-tissue,  by  which  designation  is  meant  the  appearance  of 
a  delicate  myxomatous  reticulum.  In  the  next  stage  many  of 
the  medullary  corpuscles  are  transformed  into  a  mj-xomatous 
basis-substance,  which  with  lower  powers  of  the  microscope 
looks  either  homogeneous  or  finely  granular.  Fields  of  such 
transformed  medullary  corpuscles  have  either  one  or  several 
corpuscles  unchanged,  and  are  bordered  by  a  delicate  fibrous 
reticulum  at  the  points  of  intersection,  at  which  small  oblong 
or  globular  corpuscles  are  seen.  In  this  stage  of  development 
the  tissue  is  called  purely  myxomatous. 

If,  by  a  further  splitting  up  of  the  medullary  corpuscles  into 
delicate  spindles,  the  fibrous  reticulum  is  augmented,  and  the 
fields  of  myxomatous  basis-substance  narrowed,  we  have  a  tran- 
sition from  myxoma  into  myxo-fibroma,  and  this  transition  is 
the  more  marked  the  broader  the  bundles  of  fibrous  connective 
tissue.  All  these  stages,  to  be  sure,  cannot  be  traced  in  direct 
transition  from  one  into  anothe-r,  but  we  conclude,  from  observ- 
ing the  successive  portions  of  the  same  tumor,  being  medullary 
at  the  periphery  and  fibrous  at  its  base,  that  the  former  are  the 
youngest  and  least  developed,  and  the  latter  the  oldest  and 
most  advanced. 

III.  Fibroma. — Solid  and  dense  tumors  of  a  very  slow  growth, 
starting  from  the  periosteum  of  the  jaw-bones,  are  of  rather 
frequent  occurrence  and  well  known  to  surgeons.  The  name 
given  to  them  was  "  epulis,"  which  means  a  tumor  growing 
upon  the  gum.  Obviously  this  is  a  misnomer,  since  we  know 
that  tumors  of  this  description  take  issue  as  a  rule  from  the 
periosteum,  and  invade  the  gum  in  a  rather  secondary  way. 
One  of  the  striking  features  of  such  benign  tumors  is  the  pres- 
ence of  protoplasmic  masses  with  a  varying  number  of  nuclei, 
the  so-called  giant-cells  of  previous  pathologists.  They  are 
present  in  greatly  varying  numbers,  mainly  in  that  portion  of 
the  tumor  nearest  the  periosteum,  often  being  arranged  in 
groups,  and  lacking  altogether  in  the  peripheral  portions  of  the 
growth.  (See  Fig.  295.)  "When  such  bodies  are  visible  they 
are,  as  a  rule,  surrounded  by  embryonal  tissue,  and  it  is  easy  to 
observe  their  origin  from  a  varying  number  of  medullary  cor- 
puscles. The  latter  coalesce,  thereby  losing  their  individual 
boundary  lines,  and  produce  a  uniformly  granular  mass  of  pro- 
toplasm, in    which    we    recognize    either   scattered    nuclei    or 

38 


578 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


coarser  granules,  so-called  nucleoli.  Around  the  corpuscle, 
which  is  often  of  irregular  shape,  sending  oiFshoots  into  the 
neighboring  medullary  tissue,  the  adjacent  mednllary  corpus- 
cles produce  a  kind  of  capsule,  between  which  and  the  multi- 


Era.  295. 


Base  of  Fibroma  with  MuLTiNtcLEAR  Bodies,  so-called  Giast-Gells. 

.S",  spindle-shaped  medullary  corpuscles;  /'.fibrous  basis-subftarice  haviug  originated  from 
spindle-shaped  medullary  corpuscles  ;  M,  multinuclear  body  retracted  from  the  surrounding 
medullary  tissue  ;  il/^,  multinuclear  be  dy  in  corneetion  ivilh  large  medullary  or  endothelial 
elements.     Magnified  1200  diameters. 


nuclear  bodies  a  gap  is  not  infrequently  seen, — caused,  as  it 
were,  by  the  shrinkage  of  the  "giant-cell."  It  is  known  that 
bodies  of  this  description  are  often  met  with  in  the  normal 
medullary  tissue  of  forming  and  growing  bone.     We  often  find 


TUMORS    OF    THE    JAWS.  579 

them  in  those  bay-like  excavations  that  appear  in  the  cemeutum 
and  dentine  of  temporary  teeth  during  the  process  of  their 
absorption.  The  prevaihng  idea  as  to  their  significance  is  that 
they  grow  by  coalescence  of  leucocytes  or  medullary  corpuscles, 
from  without  into  the  cement  or  dentinal  tissue,  liquefying  on 
their  way  these  tissues,  and  breaking  them  up.  Hence  their 
name,  "osteoclasts,"  or  "bone-breakers." 

We  must  decidedly  disagree  with  such  views,  since  we  have 
seen  multinuclear  protoplasmic  bodies  arising  from  the  living 
matter  of  cementum  and  dentine  itself,  after  the  dissolution  of 
the  lime-salts  and  the  liquefaction  of  the  basis-substance.  Fur- 
thermore, we  have  often  seen  such  bodies  in  the  medulla,  pre- 
ceding the  formation  of  bone-tissue.  Since  the  territories  of 
formed  bone-tissue  often  are  transformed  into  such  multinuclear 
bodies,  the  idea  becomes  admissible  that  they  can  appear  prev- 
ious to  development  of  the  osseous  territory  ;  and  to  this  view 
corresponds  their  presence  in  the  periosteal  portion  of  fibrous 
tumors.  We  admit,  however,  that  this  view  does  not  account 
for  the  presence  of  so-called  giant-cells  in  every  instance,  since, 
as  we  will  show  later  on,  they  accompany  blood-vessels,  and  are 
known  to  exist  in  inflammatory  products, — for  instance,  in 
tubercles. 

The  tumor  before  us  appeared  on  the  alveolar  process  of  the 
upper  jaw  in  the  shape  of  a  sessile  nodule,  the  size  of  half  a 
hickory-nut,  in  a  youth  about  twenty  years  of  age.  (See  Fig. 
296.) 

The  surface  of  the  tumor  looked  comparatively  smooth  to  the 
naked  eye,  but  microscopical  specimens  show  remnants  of  the 
papillse  of  the  gum,  rather  shallow  and  blunt,  and  some  distance 
apart.  The  outer  coating  is  made  up  of  stratified  epithelium, 
whose  layers  are  noticeably  diminished,  probably  owing  to  the 
pressure  of  the  growth  from  within.  The  first  row  of  columnar 
epithelia  is  well  marked  only  in  the  valleys  betw^een  the  remnants 
of  the  paj)ill?e,  while  on  their  summits  the  first  row  is  com- 
posed of  short  columnar,  or  rather  cuboidal  epithelia.  In  these 
places  both  the  epithelia  of  the  first  and  the  neighboring  epi- 
thelia of  the  adjacent  layers  exhibit  central  vacuoles,  or  plas- 
matic spaces,  from  w^hich  the  nuclei  have  dropped  out. 

The  bundles  of  the  fibrous  connective  tissue  are  of  consider- 
able breadth  throughout  the  mass  of  the  tumor,  but  their 
breadth  increases  from  the  outer  to  the  deeper  portion.     The 


580 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH, 


protoplasmic  tracts  are  well  marked  between  the  bundles,  both 
in  longitudinal  and  transverse  sections.  The  bundles  are  freely 
decussating  or  interlacing,  by  which  an  extremely  dense  trestle- 


FlBRO.MA   OF   THE   ALVEOLAE    PROCESS    OF   THE    UPPEE   JxW. 

E,  stratified  epithelium  of  the  gum  ;  P,  blunt  papilla3  of  the  gum  ;  L,  L,  longitudinal,  1\  1, 
transverse  sections  of  bundles  of  fibrous  connective  tissue  ;  C,  C,  capillary  blood-vessels.  Mag- 
nified 500  diameters. 


TUMORS    OF    THE    JAWS. 


581 


work,  similar  to  that  of  the  derma  of  the  skin,  is  produced. 
The  vessels  are  scanty  throughout  the  tissue,  consisting  mainly 
of  capillaries. 

At  the  outer  portion  of  the  tumor,  between  the  bundles, 
small  nests  of  medullary  tissue  are  discernible.  The  deepest 
portions,  on  the  contrary,  are  made  up  largel}^  of  medullary  tis- 
sue, composed  of  globular  and  spindle-shaped  corpuscles,  ^\'ith 
a  goodly  number  of  interspersed  multinuclear  bodies.  The 
latter  feature  does  not  mean  a  transformation  from  the  benign 
fibroma  into  a  malignant  myeloma,  but  the  juvenile  condition 
of  the  connective  tissue,  and  a  somewhat  accelerated  growth 
from  beneath.  This  is  proved  from  the  fact  that  the  tumor  did 
not  return  after  removal. 

IV.  Osteoma. — The  great  majority  of  bony  tumors  of  the  jaws 
are  of  the  cancellous  or  spongy  variety.  Compact  or  cortical 
osteoma  is  a  great  rarity.     The  specimen  illustrated  in  Fig.  297 

Fig.  297. 


Cancellous  Osteoma  op  Hard  Palate. 

P,  periosteum  ;  C,  thin  cortical  layer ;  T,  trabeculEe  of  cancellous  bone  ;  M,  medullary  space. 
Magnified  100  diameters. 


was  taken  from  a  tumor  the  size  of  a  small  hazel-nut,  which 
grew  in  the  median  line  ot'  the  hard  palate  near  the  soft  palate. 
A  similar  though  much  smaller  tumor  had  been  remov<-d  two 


582  THE    ANATOMY    A]S;D    PATHOLOGY    OF    THE    TEETH. 

years  previously  from  the  hard  palate  of  the  same  patient,  a 
man  about  forty  years  of  age.  The  structure  is  strictly  that  of 
epiphyseal  bone,  composed  of  osseous  trabeculse  inclosing  medul- 
lary spaces  and  surrounded  by  a  thin  cortex. 

V.  Chondroma. — A  number  of  tumors  of  cartilaginous  nature 
have  been  oljserved  upon  the  jaws  (Rokitansky,  Pitha,  Wedl, 
etc.),  all  v'ith  a  hyaline  basis-substance  in  which  protoplasmic 
bodies,  so-called  cartilage-corpuscles,  were  imbedded.  'No  speci- 
men of  this  type  of  tumor  being  at  our  disposal,  its  illustration 
is  omitted. 

VI.  Lipo -Fibroma. — In  our  collection  there  is  no  tumor  from 
the  jaws  made  up  of  fat  to  such  an  extent  as  to  warrant  a  diag- 
nosis of  lipoma.  One  specimen,  however,  removed  from  the 
lower  jaw,  the  size  of  a  cherry,  shows  a  combination  of  fibrous 
connective  with  fat-tissue,  and  thus  gives  the  variety  expressed 
in  the  title.  The  fat-globules  are  greatly  varying  in  size,  and 
either  arranged  in  groups  or  scattered  singly  in  the  connective 
tissue ;  arteries  are  accompanied  by  rows  of  such  globules. 
Most  of  the  latter  contain  vacuoles  and  peculiar  star-shaped 
formations  in  their  centers,  which  very  probably  are  not  crystals 
of  margaric  acid,  as  some  previous  observers  have  believed,  but 
remnants  of  protoplasm  which  are  known  to  exist  in  each  fat- 
globule.     (See  Fig.  298.) 

The  connective  tissue  is  of  two  kinds, — viz,  partly  broad  and 
heavy  bundles,  and  partly  narrow  spindles,  not  arranged  in 
distinct  bundles.  These  two  varieties  are  intermixed  without 
any  regularity  throughout  the  entire  tumor,  the  latter  being 
especially  conspicuous  in  the  neighborhood  of  the  fat-tissue, 
where  it  produces  a  thin  layer,  carrying  blood-vessels  between 
the  fat-globules,  or  surrounds  groups  of  them.  The  connec- 
tive tissue  contains  a  number  of  clusters  of  medullary  cor- 
puscles, which,  if  flattened  out  and  rendered  polyhedral  by 
mutual  pressure,  present  the  aspect  of  endothelia,  and  if  coal- 
esced into  one  mass  represent  multinuclear  bodies  or  giant- 
cells.  The  history  of  development  of  fat-tissue  demonstrates 
that  each  globule  of  a  larger  size  arises  from  a  number  of  medul- 
lary corpuscles,  which  are  transformed  chemically  into  fat, 
whereas  the  central  portions  remain  unchanged  protoplasm, 
with  branching  oiFshoots ;  much  on  the  plan  of  territories  with 
central  cartilage  or  bone-corpuscles.  Small  fat-globules  maybe 
the  products  of  transformation  of  single  medullary  corpuscles, 


TUMORS    OF    THE    JAWS. 


583 


or  a  limited  number  thereof.  It  has  long  been  known  that,  in 
animals  in  which  emaciation  is  induced  rapidly  by  starvation, 
each  fat-globule  breaks  np  into  a  number  of  medullary  corpus- 


Fi_;.  29.^. 


LiPO-FiBEOMA  OF   Lower  Jaw. 

i^, /",  fat-globules ;    M,  clusters  of  medullary  corpuscles;    G,  multinuclear  body  or  giant- 
cell;  ^.artery.    Magnified  400  diameteri. 


584  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

cles,— viz,  into  the  embryonal  material  wliich  originally  gave 
rise  to  the  formation  of  a  globule.  If  vre  recall  the  fact  that 
each  fat-globule  is  surrounded  by  a  thin  connective-tissue  cap- 
sule, invariably  supplied  with  a  nucleus,  fat  at  once  appears  as 
a  variety  of  myxomatous  tissue,  the  difference  being  only  a 
chemical  alteration  of  the  protoplasm  into  carbohydrates  or  fat, 
instead  of  a  mucoid  basis-substance. 

From  this  point  of  view,  the  clusters  of  medullary  or  endo- 
thelial corpuscles  would  simply  represent  a  pre-stage  of  future 
fat-globules  or  remnants  of  previous  ones.  Since  multinuclear 
bodies  or  giant-cells  are  known  to  result  from  a  coalescence  of 
medullary  or  endothelial  corpuscles,  there  is  good  reason  to 
assume  that  these  bodies  likewise  would  represent,  eventually, 
either  a  previous  or  a  past  stage  of  fat-globules.  A  fat-globule, 
according  to  our  view,  is  a  globular  territory  with  a  central  pro- 
toplasmic body,  growing  in  exactly  the  same  manner  as  a  terri- 
tory of  myxomatous,  cartilaginous,  or  osseous  tissue ;  the 
nucleus  always  belonging  to  the  capsule  around  the  globule, 
and  not  to  the  globule  itself.  A  territory  of  any  of  the  tissues 
named  will  break  up,  in  the  process  of  physiological  or  reduc- 
tion in  pathological  conditions,  into  clusters  of  medullary  cor- 
puscles, or  into  multinuclear  protoplasmic  bodies. 

VII.  Angioma. — A  boy,  eleven  years  of  age,  presented  him- 
self with  a  tumor  the  size  of  a  small  hickorjMiut  on  the  gum  of 
the  lower  jaw,  occupying  the  region  of  the  right  lateral  incisor 
and  cuspid,  having  its  rise  in  a  somewhat  narrow  pedicle  between 
the  teeth.  The  surface  was  nearly  smooth,  slightly  lobulated  ; 
its  consistence  rather  soft,  and  easily  compressible;  its  color 
dark  red.  Pressure  with  the  finger  rendered  the  tumor  pale, 
considerably  diminishing  its  bulk  at  the  same  time,  but  as  soon 
as  the  pressure  ceased  the  previous  size  and  color  returned. 
Three  months  previously  a  similar  tumor  had  been  removed 
from  the  same  place,  but  it  almost  immediately  commenced  to 
grow  again  with  alarming  rapidity,  causing  a  slightly  uneasy 
feeling,  but  no  pain. 

Vertical  sections  through  the  body  of  the  tumor  revealed  the 
fact  that  its  interior  was  composed  mainly  of  blood-vessels,  but 
that  the  outer  and  inner  portions  differed  in  structure.  The 
former  exhibited  the  features  of  a  lobular,  the  latter  of  a  cavern- 
ous, angioma. 

a.  Lobular  Angioma. — The  surface  of  the  vascular  or  erectile 


TUMORS    OF    THE    JAWS. 


585 


tumor  is  covered  with  a  stratified  epithelium,  being  normal  in 
its  breadth  at  the  borders,  and  much  thinned  in  the  middle  por- 
tions of  the  tumor.     In  the  former  places  there   are   visible 


Fig.   299. 


Lobular  Angioma  of  the  Gum  of  the   Lotver  Javt. 

^P,  stratified  epithelium  whose  columnar  epithelia  toward  the  right  side  are  breaking  up 
into  medullary  corpuscles ;  EX  endothelial  layer  traversed  by  radiating  tracts  of  a  delicate 
fibrous  connective  tissue  ;  C,  capillary  blood-vessels  in  the  endothelial  layer ;  £,  L,  lobules  com- 
posed mainly  of  capillary  blood-vessels.    Magnified  500  diameters. 


586  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

numerous  rather  shallow  papillae,  a  certahi  number  of  which  are 
united  into  a  group  by  deep  epithelial  valleys.  In  the  central 
portions  only  a  limited  number  of  layers  of  cuboidal  epithelia 
are  discernible,  the  deepest  layer  being  absent,  and  replaced  by 
medullary  corpuscles  to  such  an  extent  that  no  boundary  line 
could  be  made  out  between  the  epithelium  and  the  subjacent 
connective  tissue.     (See  Fig.  299.) 

The  connective-tissue  layer  beneath  the  epithelium  is  made 
up  of  nucleated  granular  corpuscles,  closely  packed  together, — 
so  much  so  that  they  flatten  each  other  into  broad  spindles. 
Bodies  of  this  description  are  termed  endothelia.  A  limited 
number  of  tumors  of  this  variety  have  been  described  since  Biz- 
zozero,  of  Italy,  drew  attention  to  their  occurrence,  and  dubbed 
them  endothelioma.  They  are  found  mainly  in  connection  with 
lipoma  and  angioma. 

The  endothelia  appear  to  be  arranged  in  clusters,  between 
which  delicate  tracts  of  a  fibrous  connective  tissue  run  in  a  some- 
what radiating  order,  which  tracts,  if  viewed  with  higher  powers 
of  the  microscope,  appear  to  be  made  up  of  narrow,  partly- 
nucleated  spindles.  The  tracts  spread  toward  the  periphery  in 
a  fan  shape,  and  no  clear  distinction  is  possible  here  between  the 
broad  spindles  of  the  endothelia  and  the  narrow  spindles  of  the 
tracts. 

Some  distance  below  the  epithelia,  or  close  beneath  them,  a 
large  number  of  capillaries  are  seen  cut  in  longitudinal,  oblique, 
and  transverse  sections,  which  means  that  these  blood-vessels 
are  coiled  up  into  a  lobular  shape.  Between  the  lobules  there 
are  either  tracts  of  endothelia  mixed  with  fibrous  connective 
tissue,  or  bundles  of  the  latter  alone,  and  these  interstitial  tracts 
bear  capillaries  of  their  own,  independently  of  those  within  the 
lobules. 

The  most  striking  feature  in  the  endothelial  layers  is  the 
formation  of  red  blood-corpuscles  and  blood-vessels.  At  first 
isolated  lumps  appear  in  the  endothelia,  characterized  by  a  high 
degree  of  refraction,  and  yellow  in  color.  They  are  smaller 
than  red  blood-corpuscles,  and  are  known  by  the  name  of 
"  hsematoblasts."  Increasing  in  size,  they  assume  the  appear- 
ance and  structure  of  red  blood-corpuscles.  Clusters  of 
hsematoblasts,  or  fully-formed  red  blood-corpuscles,  are  sur- 
rounded by  circular  tracts  of  endothelia  which,  being  hollowed 
out  in  part,  lead  to  the  formation  of  channels  already  filled  with 


TUMORS    OF    THE    JAWS.  587 

blood,  whereas  a  number  of  endotbelia  of  rather  large  size  fur- 
nish the  walls  of  the  capillaries.  Thus  the  formation  of  red 
blood-corpuseles  precedes  that  of  blood-vessels,  as  stated  some 
forty-iive  years  ago  by  the  late  Rokitansky,  of  Vienna.  Thus 
it  also  becomes  plain  that  the  tissue  termed  endothelioma  is, 
at  least  in  many  instances,  a  pre-stage  of  angioma.  Obviously 
the  newly-formed  blood-vessels,  though  containing  blood-cor- 
puscles from  the  very  issue,  are  closed  tubes  or  saccules,  which 
later,  through  a  continued  vacuolationof  the  endothelia,  inoscu- 
late with  already-formed  blood-vessels;  their  tenants,  the  blood- 
corpuscles,  entering  into  circulation. 

h.  Cavernous  Angioma. — The  lower  portions  of  the  tumor 
under  consideration  have  a  different  structure,  gradually  blend- 
ing with  that  of  lobular  angioma.  Here  we  notice  large  cavities, 
at  first  lined  by  several  layers  of  endothelia,  and  containing  a 
varying  number  of  red  blood-corpuscles,  until  at  last  very  large 
spaces  make  their  appearance,  filled  with  red  blood-corpuscles  ; 
and  thus  the  character  of  a  cavernous  angioma  is  established. 
(See  Fig.  300.) 

We  observe,  at  first,  tracts  of  endothelia  accompanied  by  a 
delicate  fibrous  connective  tissue,  with  irregular  calibers,  in 
which  a  liquefaction  of  a  certain  number  has  taken  place,  as 
indicated  by  their  hydropic  condition,  to  such  an  extent  that 
only  a  delicate  frame-work  of  previous  endothelia  is  discernible. 
A  certain  number  of  endothelia  have  been  transformed  into  red 
blood-corpuscles;  another  set  furnishes  colorless  blood-corpuscles, 
or  possibly  these  arise  from  the  nuclei  of  previous  endothelia. 
The  process  is  known  to  histologists  by  the  term  of  "  vacuolation 
of  the  endothelia."  The  calibers  at  first  are  very  irregular, 
being  bounded  by  several  layers  of  endothelia,  and  it  sometimes 
occurs  that  tolerably  well-formed  calibers  of  the  same  vessel  are 
connected  with  one  another  by  narrow  canals,  owing  to  the 
presence  of  little  changed  endothelia.  Blood-corpuscles  may  be 
seen  in  one  part  of  the  caliber,  and  are  absent  in  another,  so 
long  as  the  vessels  are  not  complete.  The  remaining  endothelia 
are  large,  and  supplied  with  oblong  nuclei  of  considerable  size. 

Fully-formed  cavities  in  connection  with  the  physiological 
vessels  are  characterized  by  smaller  endothelia,  not  surpassing 
in  size  those  of  normal  veins.  The  trabeculas  inclosing  the 
venous  cavities  are  made  up  of  fibrous  connective  tissue,  carry- 
ing their  own  capillary  blood-vessels.     In   many  places,  how- 


588 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


ever,  even  the  trabeculse  are  made  up  of  endotlielia,  and  it  is 
easy  of  demonstration  that  the  endothelia  are  merely  the  medul- 
lary or  embryonal  stage  of  connective  tissue,  since  we  can  trace 


Ftg.   800. 


Cavernous  Angioma  from  the  Base  of  a  Vascular  Tujtor  op  the  Gum. 

C,  C,  cavernous  spaces  filled  with  venous  blood  ;  V,  V,  capillary  blood-vessels  of  the  trabeeul» 
bounding  the  cavities  ;  E,  E,  endothelia  in  transition,  partly  into  myxomatous  and  partly  into 
fibrous  connective  tissue.    MaKnified  500  diameters. 


TUMORS    OF    THE    JAWS.  589 

its  transformation  both  into  myxomatous  and  fibrous  connective 
tissue.  This  portion  of  the  tumor  contains  solid  masses  of  a 
dense  fibrous  connective  tissue,  which  in  all  probability  are 
not  newly  formed,  but  represent  residues  of  the  former  tissue 
of  the  gum  or  the  periosteum. 

VIII.  Myeloma. — These  tumors  are  by  no  means  of  rare 
occurrence,  as  shown  by  our  comparatively  small  collection, 
which  embraces  five  specimens  of  myeloma  and  its  combina- 
tions out  of  seventeen  representatives  of  tumors  in  gener.il. 
All  these  tumors  are  considered  malignant  with  but  one  excep- 
tion, which  concerns  the  variety  termed  "  epulis  sarcomatosa," 
or,  as  we  propose  to  call  it,  fibro-myeloma.  This  variety  is 
well  known  to  surgeons  as  admitting  of  a  radical  cure  if  thor- 
oughly extirpated.  Multinu clear  bodies  are  of  such  frequent 
occurrence  that  an  authority  like  Yirchow  speaks  of  a  variety 
which  he  calls  "giant-cell  sarcoma,"  growing  in  the  majority 
of  cases  from  the  periosteum.  We  have  described,  under  a 
previous  heading,  benign  tumors,  especially  fibroma,  contain- 
ing a  varying  number  of  so-called  giant-cells  in  their  juvenile 
portions,  where  medullary  tissue  prevails,  and  we  have  empha- 
sized that  no  stress  is  to  be  laid  upon  the  presence  of  "  giant- 
cells."  If  the  tumor  is  intermixed  with  medullary  tissue 
throughout,  the  diagnosis  will  be  fibro-myeloma,  which  is  still 
of  a  low  degree  of  malignity,  as  shown  by  clinical  experience. 
We  can  state  positively  that  the  number  of  multinuclear  bodies 
is  of  great  value  for  determining  the  degree  of  malignity  in  any 
given  case.  The  greater  their  number  the  surer  it  is  that  the 
tumor  is  not  very  malignant,  and  will  not  recur  if  radically 
removed.  On  the  contrary,  the  smaller  their  number  the 
greater  is  the  malignity  and  the  danger  of  recurrence ;  whereas, 
in  the  worst  cases  of  pure  globo-  or  spindle-myeloma,  multi- 
nuclear  bodies  are  lackins:  altourether.  In  such  cases  the  dan  e'er 
to  the  life  of  the  patient  is  imminent,  in  spite  of  all  attempts 
at  thorough  eradication. 

According  to  our  nomenclature,  we  will  dwell  upon  combina- 
tions such  as  myxo-,fibro-,and  osteo-myeloma,  and  at  last  consider 
the  two  purely  malignant  forms, — viz,  globo-  and  spindle-mye- 
loma. Either  of  these  forms  may  arise  primariW  from  the  peri- 
osteum or  medulla  of  the  jaw-bones,  or  start  in  the  nasal  cavity, 
the  antrum  of  Highmore,  or  the  soft  palate,  and  invade  the 
upper  jaw  in    a   secondary  manner.     In    several   instances  of 


590 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


primary  myeloma  we  found,  in  the  tissue  of  the  tumor,  clusters 
of  pigment  indicative  of  a  previous  hemorrhage,  possibly  in 
connection  with  a  traumatism  (blow,  kick,  fall,  etc.),  which,  as 
is  admitted,  often  causes — for  reasons  unknown — the  growth  of 
malio:nant  tumors. 


Myxo-Myeloma  of  Upper  Jaw  filling  the  Antrum  of  Highmore. 

F,  tract  of  fibrous  connective  tissue  ;  F,  capillary  blood-vessel ;  iS',  S,  nucleated  protoplasmic 
tracts  branching  and  finely  interconnecting  ;  B,  B,  myxomatous  basis-substance  with  a  delicate 
reticulum  in  connection  with  the  protoplasmic  bodies.    Magnified  1200  diameters. 


a.  Mi/xo-Myeloma. — This  specimen  originally  started  on  the 
soft  palate  of  a  young  lady  near  twenty  years  of  age,  and  after 
extirpation  recurred  on  the  base  of  the  upper  jaw-bone,  invading 
in  turn  both  the  antrum  and  the  nasal  cavities.  With  low  powers 
of  the  microscope  the  tumor  shows  a  thin  investment  of  fibrous 


TUMORS    OF    THE    JAWS.  591 

connective  tissue,  fibers  from  which  penetrate  the  morbid  growth, 
scantily  supplied  with  blood-vessels,  and  producing  imperfect 
septa,  by  which  an  indistinct  alveolar  structure  results.  The 
alveoli  are  filled  with  protoplasmic  bodies,  either  globular  or 
spindle-shaped,  or  provided  with  numerous  offshoots,  by  means 
of  which  a  net-like  structure  is  established.     (See  Fig,  301.) 

Globular  corpuscles  are  arranged  in  clusters,  with  a  scanty 
intervening  basis-substance.  Spindle-shaped  corpuscles  are 
arranged  in  tracts,  freely  connecting  at  acute  angles,  and  sepa- 
rated from  one  another  by  a  slight  amount  of  a  finely-granular 
basis-substance.  This  latter  form  would  correspond  to  that 
variety  of  mj'eloma  termed  by  Virchow  "  net-celled  sarcoma." 
The  prevailing  formation  within  the  alveoli,  however,  corre- 
sponds to  the  illustration,  being  composed  of  very  large  poly- 
morphous protoplasmic  masses,  some  containing  a  number  of 
nuclei,  and  interconnected  by  comparatively  narrow  offshoots 
in  all  directions.  The  basis-substance  between  these  forma- 
tions is  conspicuous,  and  traversed  by  an  extremely  delicate 
reticulum,  which  arises  from  the  finest  offshoots  in  a  brush- 
like  manner.  This  tissue  is  myxomatous  in  structure,  the  pre- 
dominance of  which  over  the  structures  before  mentioned 
entitles  the  tumor  to  the  name  of  myxo-myeloma.  The  myxo- 
matous tissue  contains  no  blood-vessels,  which  invariably  run  in 
tracts  of  fibrous  connective  tissue,  at  rather  distant  intervals. 
As  the  consistence  of  the  tumor  was  soft,  almost  jelly-like,  the 
basis-substance  must  be  of  the  mucoid  or  myxomatous  variety. 
In  cases  where  the  basis-substance  is  more  firm  the  tumor  has 
been  termed  chondro-myeloma,  or  malignant  chondroma, 
although  we  would  consider  the  latter  term  as  illogical. 

b.  Fibro-Myeloma. — Among  several  tumors  of  this  variety, 
we  have  selected  the  present  specimen  for  description,  its  clini- 
cal history  being  better  known.  It  was  located  upon  the  right 
side  of  the  lower  jaw  of  a  man  about  thirty-five  years  of  age, 
the  size  of  half  a  hen's  o^gg^  occupying  the  space  between  the 
first  bicuspid  and  the  ramus;  the  teeth  in  this  locality  having 
previously  been  removed.  Its  consistence  was  firm,  its  surface 
slightly  nodular,  its  color  purple,  and  there  were  nowhere  signs 
of  ulceration.  For  a  while  previous  to  its  removal  it  caused 
considerable  pain  of  a  shooting  character.  It  had  grown  within 
about  two  years. 

Under  the  microscope  the  tumor  appears  to  be  composed  of 


592  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


Fig.  302. 


FlBRO-MvELOMi    WITH    MULTINTCLE AE    BODIES   FROM  THE   LoWER   JaW. 


Z,  i.  longitudinal,  T,  transverse  sections  of  bundles  of  fibrous  eonneetiye  tissue;  M,  M.  clus- 
ters of  medullary  corpuscles  ;  G,  Ci,  multinuclear  bodies  or  so-called  giant-cells,  retracted  from 
the  adjacent  connective  tissue ;  F,  blood-vessel  in  transverse  section  surrounded  by  a  cluster  of 
medullary  corpuscles.    Magnified  1200  diameters. 


TUMORS    OF    THE    JAWS.  593 

interlacing  tracts  of  fibrous  connective  tissue,  with  interstices 
filled  either  with  medullary  corpuscles  or  with  multinuclear 
protoplasmic  bodies ;  the  fibrous  portion  everywhere  being  in 
excess  ever  the  medullary  tissue.  (Fig.  302.)  The  clusters  of 
medullary  corpuscles  are  rather  numerous,  exhibiting  an  endo- 
thelial appearance.  In  some  places  blood-vessels  are  seen  to  be 
surrounded  with  or  accompanied  by  such  medullary  corpuscles, 
and  in  a  few  places  multinuclear  bodies  are  visible  in  small  num- 
bers, but  in  a  remarkably  regular  arrangement.  The  fact  that 
blood-vessels  traverse  the  clusters  excludes  their  being  of  an  epi- 
thelial nature,  and  therefore  the  diagnosis  of  cancer,  which  could 
be  made  upon  a  superficial  glance  at  the  tumor,  is  untenable. 
This  tumor  we  would  not  consider  a  very  malignant  one,  and 
the  diagnosis  of  a  fibroma  would  be  admissible  if  the  medullary 
nests  were  not  so  profusely  scattered  throughout  the  tissue. 

A  far  more  malignant  case  of  fibro-myeloma  is  the  following  : 
A  man  about  twenty-five  years  of  age  showed  a  hard  swelling 
upon  the  right  upper  maxilla,  which  had  developed  within  three 
years.  The  tumor  occupied  not  only  the  region  of  the  alveolar 
process,  but  also  the  antrum  of  Highmore.  Most  of  the  teeth 
had  become  loose  and  been  removed,  the  two  last  molars  being 
left,  but  very  loose,  and  nearly  imbedded  in  the  dark-red  mass 
of  the  tumor.  The  diagnosis  was  malignant  tumor,  either  can- 
cer or  myeloma.  The  entire  right  maxilla  was  extirpated,  and 
a  portion  of  the  alveolar  process  with  a  tooth  in  it  came  into 
our  possession. 

At  the  microscopical  examination  no  trace  of  a  bony  struc- 
ture could  be  found;  the  mass  of  the  tumor  consisting  mainly 
of  clusters  of  small  globular  shining  corpuscles,  between  which 
an  indistinct  fibrous  reticulum  was  discernible.  The  clusters 
were  separated  from  one  another  by  bundles  of  fibrous  connec- 
tive tissue,  greatly  varying  in  amount;  the  surface  of  the  tumor 
was  bordered  by  an  indistinct  capsule  of  the  same  tissue,  which 
itself  contained  smaller  clusters  of  myeloma  corpuscles,  and 
showed  irregular,  blunt  elevations  belonging  to  the  gum,  and 
covered  ^^^th  a  thin  layer  of  stratified  epithelium. 

In  the  neighborhood  of  the  tooth  the  pericementum  was  still 
recognizable,  in  the  shape  of  straight  bundles  of  fibrous  con- 
nective tissue,  still  in  connection  with  the  cementum,  but 
crowded  with  myeloma  corpuscles.     (See  Fig,  303.) 

In  this  situation  it  is  evident  that  the  tissue  of  the  myeloma 

39 


594 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


grew  at  the  expense  of  the  fibrous  connective  tissue  of  the  peri- 
cementum. In  some  places  the  bundles  of  the  latter  tissue  are 
still  broad,  containing  in  their  middle  slit-like  groups  of  medul- 


TiG.  303. 


Eibro-Myeloma  o¥  the  Upper  Jaw  invading  the  Pericementum. 

C,  cementum ;  B,  B,  bundles  of  fibrous  connective  tissue  ;  S,  S,  clusters  of  myeloma  corpuscles 
between  the  bundles  ;  ^\  transformation  of  tbe  bundles  into  the  tist^ue  of  myeloma,  -with  scanty 
traces  of  the  bundles.    Magnified  500  diameters. 


TUMORS    OF    THE    JAWS.  595 

lary  corpuscles.  In  other  places  these  corpuscles  have  replaced 
the  bundles  to  a  great  extent;  in  still  other  places,  only  scanty 
and  thin  bundles  are  seen  traversing  the  tissue  of  the  myeloma. 
At  the  last  elements  of  myeloma  occupy  large  fields,  with  scanty 
or  no  fibrous  tissue  between  them.  Obviously  the  process  of 
transformation  is  explicable  only  if  we  admit  that  the  whole  of 
the  fibrous  connective  tissue,  the  protoplasmic  bodies  as  well  as 
the  basis-substance,  is  supplied  with  living  matter,  from  which 
the  new  formation  of  the  medullary  corpuscles  takes  its  origin. 

If  we  confine  ourselves  to  the  examination  of  a  limited  portion 
of  this  tumor,  no  differentiation  between  myeloma  and  an  acute 
inflammatory  process  can  be  made  out,  since  the  medullary  cor- 
puscles constituting  myeloma  are  identical  with  inflammatory 
corpuscles  about  ready  to  break  up  into  pus.  It  should  also  be 
borne  in  mind  that  a  rapidly-growing  cancer  may  change  its 
character  into  that  of  a  myeloma,  or  fibro-rayeloma,  as  first 
stated  by  Virchow.  In  specimens  of  such  rapidly-growing 
tumors  we  have  always  to  keep  a  sharp  lookout  for  epithelial 
nests,  the  presence  of  which  would  be  evidence  of  cancer. 
Should  such  nests  be  absent,  we  diagnosticate  myeloma.  We 
are,  however,  aware  that  either  of  these  tumors  involves  con- 
siderable danger  to  the  life  of  the  patient. 

c.  Osteo- Myeloma. — This  tumor  was  found  in  the  mouth  of  a 
lady  aged  about  thirty,  in  the  region  of  the  bicuspids  upon  the 
left  upper  jaw,  and  had  reached  the  size  of  half  a  robin's  egg 
in  a  year  and  a  half,  the  teeth  having  previously  been  removed. 
The  tumor  exhibited  the  structure  of  a  fibro-myeloma,  invad- 
ing mainly  the  alveolar  process,  which  was  reduced  to  minute 
remnants  of  bone  scattered  throughout  the  tissue.  (See  Fig. 
304.) 

The  term  osteo-myeloma  is  confined  to  growths  primarily 
arising  in  the  medulla  of  bone,  or  to  growths  holding  newly- 
formed  bone-tissue.  As  the  tumor  in  this  instance  started  in 
the  medulla  of  the  alveolar  process,  and  is  largely  intermixed 
with  fibrous  connective  tissue,  its  proper  title  would  be  osteo- 
fibro-myeloma.  The  remnants  of  bone-tissue  give  evidence  of 
its  transformation  into  the  mass  of  the  tumor  through  the  inter- 
vening stage  of  medullary  tissue.  In  a  few  places  we  find  near 
the  border  of  trabeculee  enlarged  lacunae  containing  several 
medullary  corpuscles,  obviously  sprung  from  previous  bone- 
corpuscles,  and  still  surrounded  by  a  calcified  basis-substance. 


596 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


In  other  places  a  number  of  bone-corpuscles  are  seen  connected 
by  means  of  broad  offshoots  into  chains.  In  still  others,  the 
first  step  toward  the  dissolution  of  the  bone-tissue  is  the  appear- 


FiG.  304. 


Osteo-Fibro-Myeloma  of  the  Alveolar  Process  of  the  Upper  Jaw. 

F,  F,  fibrous  conneetire  tissue  with  numerous  clusters  of  medullary  corpuscles;  P,  P,  clusters 
of  pigment-granules  ;  B,  trabeculfe  of  bone  indistinctly  lamellated,  with  normal  bone-corpuscles ; 
H,  medullary  space  with  central  blood-vessels  ;  D,  bay-like  excavation  of  the  bone.  Magnified 
500  diameters. 


TUMORS    OF    THE    JAWS. 


597 


ance  of  bay-like  excavations  corresponding  to  a  previous  terri- 
tory, in  whicli  protoplasm  makes  its  appearance ;  or  the  border 
of  the  bone  is  split  up  into  a  number  of  medullary  corpuscles, 
which  are  not  yet  entirely  freed  from  basis-substance.  All 
this  is  strong  proof  that  the  bone  actively  participates  in  the 
new  formation  of  the  morbid  tissue,  the  same  as  it  participates 
in  the  process  of  inflammation.  To  say,  as  some  authors  do, 
that  the  bone  is  simply  eaten  up  from  without  by  the  newly- 
formed  tissue,  does  not  prove  much  acuteness  of  observation, 
since  it  is  by  no  means  difficult  to  satisfy  one's  self  as  to  the 
active  proliferation  of  the  bone-corpuscles  within  the  lacunae. 
It  is  invariably  the  medullary  corpuscles  that  first  appear  from 
bone-tissue,  and  by  subsequent  splitting  into  spindles  and  rein- 
filtration  with  basis-substance  give  rise  to  the  fibrous  portion 
of  the  morbid  growth. 

Fig.  305. 


Globo-Myeloma  of  the  Periosteum  of  the  Alveolae  Process  of  the  Upper  Ja'R'. 

B,  delicate  bundles  of  fibrous  connective  tissue  ;  G,  globular  corpuscles  of  myeloma  in  dif- 
ferent stages  of  development.    Magnified  1200  diameters. 


d.  Gloho-3Iyeloma. — This  specimen  was  obtained  from  a 
tumor  taken  from  the  mouth  of  a  young  lady  about  twenty 
years  of  age.  It  was  located  on  the  right  upper  jaw,  in  the 
region  of  the  bicuspids,  and  had  grown  to  the  size  of  half  an 
English  walnut  in  about  two  years.  The  teeth  had  previous!}' 
been  removed.  It  was  diffusely  infiltrated  toward  the  neigh- 
boring tissue,  and  evidently  started  from  the  periosteum.  (See 
Fig.  305.) 


598  THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 

The  most  striking  feature  was  the  scarcity  of  fibrous  connec- 
tive tissue,  which  in  delicate  bundles  traverses  the  growth  with- 
out any  regularity.  The  main  mass  is  composed  of  medullary 
corpuscles,  either  globular  or  polygonal,  the  latter  produced  by 
mutual  pressure.  Between  small  groups  of  such  corpuscles 
extremely  delicate  septa  of  fibrous  tissue  are  visible,  in  which 
the  blood-vessels  are  located,  though  present  only  in  small 
numbers. 

Higher  powers  reveal  two  facts, — viz,  first,  that  the  corpuscles 
are  interconnected  by  delicate  radiating  offshoots,  traversing  the 
narrow  spaces  between  them;  second,  that  in  a  limited  field 
of  the  tissue  all  stages  of  development  of  myeloma  can  be  made 
out. 

We  see  small  granules  of  a  high  refraction,  structureless,  not 
even  reaching  the  size  of  red  blood-corpuscles.  We  see  larger 
granules  and  lumps  with  a  varying  number  of  vacuoles  in 
their  interior.  We  furthermore  see  lumps  with  large,  com- 
pact nuclei,  and  at  last  corpuscles  with  reticulated  nuclei,  with 
granules  in  their  interior,  and  of  the  ordinary  reticulated  struc- 
ture of  protoplasm.  Any  granule  within  the  protoplasm  may 
grow  to  the  size  of  a  nucleus,  or  a  nucleated  corpuscle ;  the 
nuclei  themselves  are  in  an  active  process  of  division,  as  shown 
by  numerous  dumb-bell  forms,  and  figures  of  double  or  treble 
nuclei  within  a  single  corpuscle.  All  this  is  proof  of  a  very 
rapid  multiplication  of  the  corpuscles,  causing  an  extremely 
rapid  growth  of  the  tumor,  and  indicative  of  a  high  degree  of 
malignancy.  In  accord  Mnth  the  latter  features,  not  a  single 
multinuclear  body  or  "  giant-cell"  can  be  seen,  not  even  where 
somewhat  broader  bundles  of  fibrous  tissue,  probably  belonging 
to  the  periosteum,  are  present. 

e.  Spindle- 31yeloma. — This  tumor,  corresponding  to  what  Vir- 
chow  has  termed  "  spindle-celled  sarcoma,"  is  represented  in  our 
collection  by  a  specimen,  the  history  of  which  is  unknown  to  us. 
All  we  can  say  is  that  it  had  grown  in  the  upper  jaw.  (See 
Fig.  306.) 

The  tumor  is  largely  composed  of  spindles,  but  in  some  places 
globular  corpuscles  are  seen,  which  feature  would  entitle  the 
tumor  to  the  name  of  a  combined  globo-  and  spindle-myeloma. 
The  tumor  has  comparatively  little  of  fibrous  connective  tissue, 
in  which  scanty  blood-vessels  are  coursing.  The  spindles  are 
arranged  in  interlacing  groups, — in  almost  every  field  we  meet 


TUMORS    OF    THE    JAWS. 


599 


with  longitudinal  and  transverse  sections  of  spindles,  all  of 
which  are  interconnected  by  delicate  offshoots.  The  rapid 
growth  of  the  tumor  is  indicated  mainly  by  coarsely-granular 
nuclei,  or  chains  of  coarse  granules,  replacing  the  nuclei.  In 
some  places  clusters  of  red-brown  pigment-granules  are  seen, 
but  in  such  small  numbers  that  the  tumor  cannot  be  properly 
called  pigmented  or  melanotic  myeloma.  The  pigment  appears 
either  in  spindle-shaped  or  irregular  clusters,  partly  within  and 
partly  between  the  spindle-shaped  corpnscles.  These  pigment- 
clusters  are  unquestionably  the  result  of  a  previous  hemorrhage. 

Fig.  306. 


Spindle-Myeloma  of  Upper  Jaw. 

L,  L,  longitudinal  sections  of  spindles;   T,  T,  transverse  sections  of  spindles;  P,  P,  clusters 
of  pigment  from  previous  hemorrhage.    Magnified  1200  diameters. 


possibly  caused  by  a  mechanical  injury,  giving  issue  to  the  mye- 
lomatous  new  growth. 

IX.  Papilloma  or  Warty  Tumor  is  rare  upon  the  mucous 
membrane  of  the  oral  cavity.  By  direct  venereal  infection 
the  tonsils  and  the  soft  palate  of  women  may  become  covered 
with  so-called  venereal  warts,  which  in  fact  are  papillary  out- 
growths of  the  oral  mucosa,  sometimes  attaining  the  size  of  a 
pea,  and  being  present  in  large  numbers.  In  men,  upon  the 
mucosa  covering  the  hard  palate,  warty  tumors  not  of  venereal 
origin  have  been  observed,  varying  from  the  size  of  a  pin-head 


600 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


to  that  of  a  split  pea.  The  specimen  from  which  the  illustra- 
tion is  taken  was  of  the  latter  size,  and  had  grown  upon  the 
hard  palate  of  a  middle-aged  married  man.     (See  Fig.  307.) 


Tig.  307. 


LLoRXY  Papilloma   of  Hard   Palate   op   a  Max. 

E,  epidermal  layer;  R,  rete  mueosum;  L,  papilla  in  longitudinal  section:  0,  papilla  in 
oblique  section  ;  T,  papilla  in  transverse  section  ;  C,  fibrous  connective  tissue.  Magnified  50 
diameters. 


The  characteristic  feature  of  such  tumors  is  their  warty  sur- 
face, owing  to  the  presence  of  papillse  covered  with  a  heavj 
layer  of  stratified  epithelia.  The  papillae  are  outgrowths  of  the 
connectire  tissue  of  the  mucous  membrane,  and  are  often  richly 
supplied  with  blood-vessels.     (See  Fig.  308.) 

Tumors  of  papillary  structure  are  known  to  be  ditficult  of 
eradication.  Unless  thoroughly  extirpated  they  are  prone  to 
recur,  and  repeated  attempts  at  eradication  may  cause  a  change 
of  the  tumor  into  a  malignant  cancer,  generally  of  the  type  of 
epithelioma. 


TUMORS    OF    THE    JAWS. 


601 


X.  Cysto-Adenoma. — Glandular  tumors  of  the  jaws,  the 
mucous  membrane  of  which  abounds  in  mucous  glands,  are 
nevertheless  of  rare  occurrence.  A  combination  of  adenoma 
with  cystic  cavities  is  extremely  rare.  The  case  to  be  consid- 
ered came  under  the  observation  of  Dr.  Wm.  Carr,  who  kindly 

Fig.  308. 


HoKXY  Papilloma  of  Hard  Palate. 

T,  papilla  in  transverse  section  :  bundles  of  fibrous  tissue  in  longitudinal  and  transverse  sec- 
tion, with  protoplasmic  tracts  between  the  bundles  :  F,  capillary  blood-vessel ;  C,  row  of  col- 
umnar epithelia  ;  7?,  rete  mucosum  composed  of  cuboidal  epithelia;  i^,  horny  layer,  composed 
of  flat  epithelia.    Magnified  500  diameters. 


furnished  the  details  of  the  history,  and  supplied  me  with  a 
freshly-excised  piece  of  the  tumor  for  study.  The  tumor  had 
begun  to  grow  npon  the  left  side  of  the  lower  jaw,  behind  the 
second  molar,  when  the  patient  was  seventeen  years  of  age ;  and 


602 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


when  lie  laacl  readied  the  age  of  nineteen,  it  had  grown  to  the 
size  of  a  goose's  egg.  It  was  soft  and  fluctuating  to  the  touch, 
and  bled  profusely  upon  the  slightest  mechanical  injury. 

The  basis  of  the  cyst,  from  which  the  specimen  was  taken, 


Fig.  309. 


Cysto-Adenoma  of  Lower  Jaw. 

S,  surface  toward  cystic  cavity,  with,  numerous  epithelial  prolongations ;  /"",  myxo-fibrous 
connective  tissue ;  N,  nodule  of  myxomatous  tissue,  freely  vascularized  ;  G,  fibrous  connective 
tissue ;  /,  /,  enlarged  glandular  cavities  filled  with  indifferent  elements  ;  M,  myxomatous  tissue, 
sprung  from  epithelia  ;  6,  unchanged  glandular  formations.    Magnified  50  diameters. 


proved  to  be  made  up  largely  of  acinous  glands  of  great  irregu- 
larity, lined  partly  by  cuboidal  and  partly  by  short  columnar 
epithelia.     (See  Fig.  309.)     With  higher  powers  of  the  micro- 


TUMORS    OF    THE    JAWS. 


603 


scope  a  peculiar  change  of  the  epithelia  became  noticeable, 
much  resembling  that  of  the  epithelia  of  the  enamel-cord  pre- 
ceding the  production  of  the  enamel-organ  in  the  normal 
development  of  the  teeth.     In  the  tumor  a  great  many  epithe- 


FiG.   310. 


Cysto-Adenoma  of  Lowee  Jaw. 

E,  row  of  columnar  epithelia  lining  the  gland ;  T,  top  view  of  columnar  epithelia  ;  M,  medul- 
lary tissue,  sprung  from  epithelia ;  S,  basement-membrane  around  the  glands  ;  F,  F,  fibrous 
connective  tissue  between  the  glands  ;  C,  capillary  blood-vessel  in  transverse  section.  Magni- 
fied 500  diameters. 

lia  were  transformed  into  solid  indifierent  or  medullary  cor- 
puscles, from  which,  in  turn,  mj'xomatous  tissue  developed. 
Close  to  the  lining  epithelia  we  frequently  meet  with  a  layer 
bearing  resemblance  to  the  intermediate  layer  of  the  enamel- 


604  THE    ANATOMY    AND    PATHOLOaY    OF    THE    TEETH. 

organ.  By  a  gradual  liquefaction  of  the  myxomatous  tissue 
cystic  cavities  of  varying  sizes  arise,  and,  no  doubt,  the  main 
cystic  cavity  in  this  case  owed  its  origin  to  such  a  change  in 
the  intra-glandular  myxomatous  tissue.     (See  Fig.  310.) 

XI.  Carcinoma. — This  type  of  tumors  is  characterized  by  the 
presence  of  epithelial  nests,  scattered  without  regularity  in  the 
connective  tissue,  which  may  be  either  myxomatous  or  fibrous. 
Most  pathologists  claim  that  cancer  may  originate  only  in  such 
tissues  as  are  covered  with  or  contain  normal  epithelia.  The 
mucosa  of  both  the  oral  and  nasal  cavities  is  the  starting-point 
of  cancerous  growths,  and  in  the  upper  jaw  there  is  an  additional 
source  in  the  mucosa  of  the  antrum.  Again,  the  cancer  may  be 
primary  in  the  tissue  just  named,  or  secondary  by  invasion  from 
the'  skin  or  any  glandular  formation, — for  instance,  from  the 
salivary  glands. 

There  are  three  varieties  of  cancer  recognized  by  modern 
pathologists, — viz,  first,  scirrhus,  with  comparatively  small  nests 
of  epithelia,  and  a  large  amount  of  fibrous  connective  tissue 
around  the  nests;  second,  epithelioma  or  dermoid  cancer,  with 
concentrically-arranged  flat  epithelia  filling  the  nests,  and  a 
varying  amount  of  fibrous  tissue  between  them ;  and,  third, 
medullary  cancer,  with  small  and  irregular  epithelia  in  the 
nests,  and  a  scanty  fibrous  tissue  between  them.  Of  these  three 
varieties  our  collection  has  two, — viz,  epithelioma  and  medullary 
cancer,  both  having  reached  the  upper  jaw  from  adjacent  epithe- 
lial structures,  skin  and  mucous  membrane. 

a.  Epithelioma,  or  Dermoid  Cancer. — "We  have  two  examples 
of  this  type  of  cancer,  both  from  men  over  forty  years  of  age. 
In  one  the  tumor  arose  in  the  mucosa  of  the  antrum,  and  in  the 
other  in  that  of  the  floor  of  the  nasal  cavity,  both  being  similar 
in  structure.     (See  Fig.  311.) 

In  viewing  a  specimen  of  epithelioma  from  the  mucosa  of  the 
antrum,  we  observe  marked  dififerences  in  the  structure  of  the 
epithelia.  jSTear  the  boundary  toward  the  connective  tissue  they 
are  smaller  and  narrower  than  in  the  middle  portions  of  the 
nests.  They  are  often  replaced  by  a  row  of  medullary  corpuscles, 
to  such  an  extent  that  no  sharp  boundary  line  exists  between 
the  connective  tissue  and  the  epithelial  nest.  This  obviously 
means  a  gradual  transformation  of  the  medullary  into  epithelial 
tissue,  a  process  which  leads  to  increase  of  the  bulk  of  the  nests 
and  a  decrease  of  that  of  the  connective  tissue.     At  last,  the 


TUMORS    OF    THE    JAWS. 


605 


blood-vessels  being  finally  obliterated,  the  nests  are  deprived  of 
nourishing  material,  and  a  local  necrosis — viz,  ulceration — 
takes  place,  which  is  a  common  feature  in  all  cancers. 

The  second  prominent  feature  is  an  active  new  formation  of 


Epithelioma  of  the  Mucosa  of  the  Antrum. 

C,  delicate  fibrous  connective  tissue  crowded  with  medullary  corpuscles  ;  V,  capillary  blood- 
vessel in  the  connective  tissue ;  E,  E,  epithelial  nests  made  up  of  concentrically-arranged  flat 
epithelia  ;  P,  P,  cancer-pearls  composed  of  changed  epithelia.    Magnified  500  diameters. 


606  THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 

living  matter  in  the  epithelia.  This  causes  the  nuclei  to  liecome 
homogeneous;  then  to  assume  an  hour-glass  shape,  and  lastly  a 
division  into  several  nuclei.  ]S^ot  infrequently  we  see  several 
nuclei  or  several  medullary  corpuscles  within  a  considerably 
enlarged  epithelium.  Such  formations  have  been  termed 
"  mother-cells"  by  previous  pathologists,  whereas  to-day  we 
know  that  they  are  the  outcome  of  an  active  endogenous  new 
formation.  Around  the  nucleus  often  are  seen  vacuoles,  or 
plasmatic  spaces,  which  evidently  contain  nourishing  liquid, 
enabling  the  nucleus  to  rapidly  increase  its  amount  of  living 
matter,  with  the  result  of  iission  and  division,  with  a  rapid  new 
formation  of  epithelia.  Except  where  the  nucleus  is  surrounded 
by  a  vacuole,  it  is  in  connection  with  the  adjacent  protoplasm  of 
the  epithelium,  by  means  of  delicate  conical  otishoots.  Similar 
offshoots  also  traverse  the  cement-substance  between  the  epithe- 
lia, thus  uniting  all  into  a  continuous  mass  of  protoplasm.  The 
central  portions  of  the  nests  often  contain  groups  of  epithelia, 
which  have  assumed  a  high  degree  of  refraction,  a  yellowish 
color,  and  a  homogeneous  appearance.  At  first  the  nuclei  re- 
main, though  faintly  discernible;  but  in  the  more  advanced 
degrees  of  this  metamorphosis  even  the  traces  of  nuclei  are  lost, 
and  a  certain  number  of  epithelia  are  transformed  into  structure- 
less glistening  plugs,  representing  the  well-known  cancer-pearls. 
The  nature  of  this  process  is  not  yet  known. 

The  connective  tissue  is  either  of  the  myxomatous  or  fibrous 
variety,  never  very  rich  in  blood-vessels;  mainly  capillaries 
and  veins.  In  many  places  the  connective  tissue  is  crowded 
with  medullary  or  lymph-corpuscles,  between  which  a  delicate 
reticulum  is  seen.  Some  authors  claim  that  this  is  the  result 
of  an  inflammatory  reaction  of  the  epithelial  upon  the  connec- 
tive tissue;  whereas  we  claim  that  it  is  the  medullary  condition 
of  the  connective  tissue  from  which  new  epithelia  arise.  We 
base  our  views  upon  direct  observation,  since  we  know  that  if, 
after  removal  of  a  cancer,  lymph-corpuscles  be  left  behind,  even 
though  at  a  great  distance  from  the  cancer  itself,  the  disease 
will  invariably  recur.  This  fact  urges  the  necessity  for  removal 
of  large  portions  of  tissue  in  the  neighborhood  of  cancer.  Mod- 
ern surgeons,  by  clinical  experience,  have  reached  the  same 
conclusion,  which  they  consider  the  only  safeguard  against  re- 
lapses, so  very  common  in  this  disease.  Unfortunately,  we  are 
not  able  to  say  why  the  lymph-corpuscles  or  the  medullary  tissue, 


TUMORS    OF    THE    JAWS.  607 

into  which  the  connective  tissue  is  transformed  in  an  almost 
identical  way  with  inflammatory  infiltration,  should  have  such 
a-  marked  capacity  for  changing  into  epithelia;  in  other  words, 
wherein  the  contagion  of  the  tissue  lies. 

b.  Medullary  Cancer. — Our  specimen  is  taken  from  the  enor- 
mously enlarged  alveolar  process  of  the  upper  jaw  of  a  man 
over  sixty  years  of  age.  Twelve  years  pre^dous  to  his  death  he 
was  first  operated  upon  for  a  so-called  rodent  ulcer,  upon  the 
left  wing  of  the  nose,  which  about  fifteen  years  previously  had 
originated  from  a  slight  injury,  causing  a  shallow  ulcer,  which 
could  never  be  induced  to  heal.  The  scooped-out  particles  of 
tissue  from  the  first  operation  were  examined  under  the  micro- 
scope, and  showed  the  structure  of  a  shallow  or  flat  epithelioma, 
which  previous  authors  termed  "rodent  ulcer." 

Repeated  recurrences  and  operations  took  place  afterward, 
until  the  left  upper  jaw  began  to  swell,  the  left  eye  was  pushed 
up  and  forward,  and  the  teeth  became  so  loose  and  troublesome 
that  they  had  to  be  removed.  Tbe  swelling  of  the  face  proved 
to  be  greatly  augmented  by  an  apparently  long-standing  abscess 
in  the  antrum,  the  result  of  the  death  of  a  second  molar  many 
years  before,  the  roots  of  which  penetrated  its  floor.  Upon  the 
removal  of  this  tooth  a  large  quantity  of  foetid  pus  escaped,  and 
a  temporary  improvement  was  the  result.  Later  the  swelling 
invaded  the  front  of  the  mouth  and  passed  to  the  right  side  to 
such  a  degree  that  several  operations  were  required  to  remove 
the  fungoid,  easily-bleeding  masses  of  the  alveolar  process, 
gum,  and  hard  palate,  which  were  almost  choking  the  patient. 
The  purpose  of  these  operations  was  not  to  remove  the  cancer, 
but  to  prevent  death  from  sufibcation  or  starvation.  This 
tumor  is  a  type  of  medullary,  cancer.     (See  Fig.  312.) 

The  specimen  exhibited  in  some  places  an  almost  unchanged 
stratified  epithelium  covering  the  papillae  of  the  gum.  In  other 
places  the  papillae  were  much  enlarged  and  flattened.  Still 
further,  the  papillae  have  entirely  disappeared  and  the  epithelial 
layer  is  considerably  thinned,  until  at  last  the  epithelium  has 
disappeared,  and  an  ulcerating  cancer-tissue  appeared  upon  the 
surface.  In  those  places  where  the  epithelial  stratum  of  the 
gum  appears  thinned,  the  deepest  or  columnar  row  of  epithelia 
as  well  as  the  lower  layers  of  cuboidal  epithelia  are  absent,  and 
are  replaced  by  a  medullary  tissue  of  a  myxomatous  character, 
which   has   incidentally  sprang   from   the   previous   epithelia. 


608 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


"We  feel  the  more  confident  of  such  change  having  taken  place 
from  the  fact  that  at  the  border  between  the  epithelial  and 
medullary  tissues  the  epithelial  bodies  themselves  show  a 
marked  increase  of  living  matter,  and  a  gradual  transforma- 
tion into  medullary  corpuscles. 

Fig.  312. 


Medullary  Caxcer  of  the  Left  Upper  Jaw,  ixvading  the  Alveolar  Process  and 

Gum. 

N,  N,  nests  of  irregular  polyhedral  epithelia ;  C,  C,  delicate  fibrous  connective  tissue  between 
the  nests ;   V,  vein.    Magnified  1200  diameters. 


Close  beneath  the  medullary  layer  nests  of  epithelia  make 
their  appearance,  separated  from  one  another  by,  first,  medul- 
lary, and  deeper  down  by  a  delicate  fibrous  connective  tissue, 
which  latter  has  evidently  originated   from  the  former.      We 


MALFORMATIONS    AND    MALPOSITIONS    OF   THE    TEETH.  609 

therefore  maintain  that  a  medallarj  tissue  which  arose  from 
previous  normal  epithelia  may  change  into  fibrous  connective 
tissue,  and  vice  versa,  that  medullary  tissue  which  arose  from 
connective  tissue  may  eventually  be  converted  into  epithelia  of 
cancer. 

The  medullary  nests  are  made  up  of  very  irregular  bodies, 
which  by  pressure  have  assumed  a  polygonal  form.  In  many 
instances  a  whole  nest  or  a  portion  of  it  is  made  up  of  granular 
protoplasm,  with  nuclei  scattered  at  regular  intervals,  without 
any  intervening  cement-substance.  Where  the  latter  is  present 
in  the  shape  of  a  narrow  ledge,  it  is  invariably  pierced  by  deli- 
cate offshoots  or  thorns,  interconnecting  the  single  epithelial 
•elements.  The  changes  of  the  epithelia  toward  proliferation 
are  much  the  same  as  in  the  epithelioma  before  described. 
The  connective  tissue  shows  a  transformation  into  lymph-tissue 
to  a  great  extent.  Where  it  has  retained  its  fibrous  character 
it  is  scanty,  separating  the  epithelial  nests  and  carrying  a  large 
number  of  protoplasmic  bodies.  The  blood-vessels  running 
therein  are  scanty,  and  prevailingly  capillaries  and  veins.  The 
latter  often  show  sinuous  contours,  and  are  replete  with  blood- 
corpuscles.  As  stated  under  the  heading  of  epithelioma,  the 
secret  of  the  general  and  local  contagiousness  of  cancer  has 
never  been  unveiled,  but  is  left  for  future  discovery. 


CHAPTER  XLYIIL 

MALFORMATIONS  AND  MALPOSITIONS  OF  THE  TEETH. 

I.  Dwarf  Teeth. — In  Chapter  XVIII,  on  the  development  of 
teeth  in  embryos  afifected  with  rhachitis,  dwarf  teeth  from  the 
lower  jaws  of  a  foetus  affected  with  congenital  rhachitis  are 
illustrated  and  described.  In  rare  instances  we  find  the  dentures 
of  adults  made  up  of  normal  teeth  with  dwarfed  third  molars 
in  the  upper  jaw.* 

II.  Hyperplasia  of  Roots. — In  Chapter  XXX  I  have  copied 
from  Frank  Abbott's  paper  a  number  of  teeth,  the  roots  of 
which  were  affected  with  hyperostosis  of  the  cementum,  caus- 
ing pronounced  malformations. 

*  In  Chapter  XLYI,  Fig.  284,  dwarfed  and  malformed  teeth  are  depicted  as 

found  in  a  dentigerous  cyst  of  the  upper  jaw. 

40 


610 


THE    ANATOMY    AND    PATHOLOGY    OF    THE    TEETH. 


Fig.  313. 


III.  Supernumerary  Teeth. — ]^ot  infrequent!}^  we  see  super- 
numerary teeth  in  temporary  dentures,  usually  behind  the  upper 
lateral  incisors.  Such  teeth  are  smaller  than  normal  ones,  and 
of  a  more  or  less  conical  shape,  hence  German  authors  have 
dubbed  them  "peg  teeth."  (See  Fig.  313.)  In  rare  cases  there 
are  present  three  bicuspids  on  one  side  of 
the  upper  jaw,  and  only  one  on 
the  other  side.  Two  or  even 
three  third  molars,  or  wisdom- 
teeth,  may  be  found  on  one  side 
of  the  upper  jaw,  while  the  op- 
posite side  has  only  one.  E. 
Zuckerkandl  has  seen  epithelial 
germs — i.e.,  enamel  pegs  not  de- 


FiG.  314. 


Supernumerary  Teeth. 
(From  Wedl.) 

A,  supernumerary  tooth    ^^l^^^^    ^^to     teeth— behind    the 


IV.  Lobulation  of  Crowns. 


lobulated 
Crown, 

probably  of 
A  Lower 
Bicuspid. 

(From  Wedl  ) 


of  the  right  side  of  the  up- 
per jaw,  between  the  first    third  molarS. 
and  second  bicuspids  toward 
the  palate  ;   JB,  supernum- 
erary tooth  of  the  upper  Occasionally  the  crowns  of  teeth 

jaw,  implanted  in  the  pal-  ,..,,. 

ate  behind  the  incisors.        are  divided  into  tmger-like  lob- 
ules.    The  illustration  (Fig.  314) 
represents  a  tooth,  probably  a  bicuspid  of  the  lower  jaw,  with 
this  anomaly. 

V.  Devious  Course  of  Roots. — This  anomaly  is  not  very  rare, 
and  is  a  great  obstacle  to  the  extraction  of  the  tooth.     The 


Fig.  315. 


Fig.  316. 


Left  Upper  First  Molar  (Carious),  with 
Devious  Roots. 


Two  Lower  Molars  with  Devious  Roots, 
(From  Wedl.) 
A,  lower  third  molar  with  fused  roots,  hooked 
and  thickened  by  hyperplastic  cementum ;  £, 
lower  third  molar,  the  anterior  root  pushed 
through  an  opening  of  the  posterior,  likewise 
hooked  on. 


deviations  are  so  manifold  that  a  description  is  scarcely  possible. 
I  attach  three  illustrations,  one  from  a  left  upper  molar  of  my 
own  collection,  and  two  from  Wedl's  Atlas.  (See  Figs.  315 
and  316.) 


MALrOR3IATIONS    AND    MALPOSITIONS    OF    THE    TEETH. 


611 


VI.  Multiplication  of  Roots.— This  anomaly  is  by  no  means 
rare.  I  have  seen  lower  lateral  incisors  with  two  roots,  of  which 
I  give  an  illustration;  a  lower  cuspid  with  three  distinct  small 

roots;    a  first   upper 


Fig.  317. 


Fig.  318. 


Teeth  TriTH  Double  axd 
Multiple  Roots. 


bicuspid  with  three 
distinctly  separated 
roots ;  first  lower 
molar  vt^ith  three  pro- 
nounced roots,  two 
in  the  mesial  and 
one  in  the  distal  por- 
tion of  the  crown. 
Wisdom-teeth     with 


Fusion  of  Two  Lotter  In- 
cisors.   (From  Abbott.) 
A,  left  lower  lateral  incisor, 

with  double  root,  symmetrical  as  many  as  five  roots  are  not  uncommon. 

with  the  root  of  the  opposite    /g        ^-        gjy  x 
side ;    B,   molar  of  the  lower    V  ^  / 

jaw.  with  five  well-developed      VII.  FusloH  of  Crowns  of  Teeth. — Frank 
Abbott,  in  the  Dental  Cosmos,  1891,  de- 
scribes two  lower  incisors  fused  together  at  their 
crowns  and  necks.     (See  Fig.  318,  a,  b.)  ^'^'-  ^'^^■ 

VIII.  Fusion  of  Roots  is  likewise  of  not  in- 
frequent occurrence,  especially  in  the  wisdom- 
teeth.  Fig.  319,  taken  from  Wedl's  Atlas,  repre- 
sents an  upper  molar  wdth  a  regularly-developed 
crown  and  completely-fused  roots. 

IX.  Fusion  of  Two  Teeth. — This  anomaly  is  of 
rare  occurrence.  Abbott  {loc.  cit.)  illustrates  a 
fusion  of  the  second  lower  molar  wdth  the  third 
molar  by  hyperplastic  cementum.     (See  Fig.  320, 

a,  b.)     C.  "Wedl  met  with  a  permanent  upper  central  fused  with 
the  lateral  incisor.     (See  Fig.  321.) 

Fig.  320.  Fig.  321. 

I 


Upper  Molar 

WITH 

Fused  Roots. 
(From  Wedl.) 


Fusion  of  Two  Molars. 
(From  Abbott.) 


Fusion  of  Left  Permanent  Upper  Central 

AND  Lateral  Inoisoe.     (From  Wedl.) 

A,  labial  surface,  showing  faint  line  of  union 

of  the  two  teeth  ;  B,  lingual  surface,  line  of 

union  marked  both  on  roots  and  crown. 


612 


THE    ANATOMY   AND    PATHOLOGY    OF    THE    TEETH. 


Fig.  322. 


X.  Breach  in  the  Continuity  of  the  Crown, 

{loc.  cit.)  illustrates  this  rare  occurrence  on 
incisor,  which  probahly 
finds  its  explanation  in 
a  fracture  or  breach  of 
the  crown,  shortly  after 
its  formation,  while  still 
covered  with  soft  tissue. 
(See  Fig.  322,  a,  h.) 

XI.  Healed  Frac- 
tures of  Teeth. — A 
small  number  of  well- 
observed  instances  of  healed  fractures  are  re- 
corded in  the  literature.  I  have  chosen  for 
illustration  the  case  of  H.  Hertz.*    The  tooth, 

Fig.  324. 


— Frank  Abbott 
an  upper   lateral 

Fig.  323. 


Breach  at  the  Neck  or  Is 
cisoES.    (From  Abbott.) 


Healed  Fracture  of 
Left  Upper  Lat- 
eral IxcisoR.  (From 
H.   Hertz.)  The 

Tooth  viewed  from 
Behind  and  Above. 
C,    crown ;     R,    root 
with  two  exostoses;  E, 
newly-formed   enamel- 
ridge. 


LiL-^ 


Healed    Fracture    of    the    Left     Upper    Lateral    Incisor.    Transverse    Section. 

(From  H.  Hertz.) 
E,  enamel;  ER,  enamel-ridge  ;  D,  broken-off  enamel;  F,  V,  vascular  canals,  around  which 
the  dentinal  canaliculi  radiate ;  P,  pulp-chamber  ;   R,  root-canal ;  C,  C,  layer  of  cementum, 
between  which  an  island  of  dentine  (D,  upper)  has  formed.    Magnified  8  diameters. 


*  "  Ein  Fall  Geheilter  Zaliiifnictur. 


Virchow's  Archiv,  1867. 


MALFORMATIOXS    AXD    MALPOSITIOXS    OF    THE    TEETH. 


613 


a  left  upper  central,  was  extracted  from  a  girl  eighteen  years  of 
age,  who  about  eight  years  previously  had  a  fall,  after  which  the 
tooth  changed  its  position  and  became  painful.  Microscopical 
examination  revealed  the  peculiar  fact  that,  in  consequence  of 
the  injury, — the  direction  of  the  fracture  being  probably  the 
fissure  seen  in  Fig.  324  on  the  left  upper  periphery  of  the  crown, 
— a  marked  new  formation  of  enamel  {EB)  took  place.  A 
second  remarkable  feature  is  the  formation  of  several  vascular 
canals  (  V,  V)  in  the  dentine,  around  which  the  canaliculi  take  a 
fan-like  course.  Inexplicable  is  the  fact  that  at  the  apex  of  the 
root,  between  two  layers  of  cementum,  a  layer  of  dentine  had 
formed.     (See  Fig.  324.) 

Fig.  325. 


Right  Upper  Lateral  Ixcisor  ix  a  Horizontal  Position.  Natural  Size.  (From  Wedl.) 
^,  edge  of  the  tooth  protruding  on  the  surface;  G',  imperfect  lateral  temporary  incisor;  C, 
empty  alveoli. 


XII.  Malpositions  of  the  Teeth  are  quite  frequent,  and  too 
variable  to  be  enumerated  in  any  particular  way.  As  many 
excellent  works  have  been  written  on  this  subject,  T  refer  those 
who  take  special  interest  in  this  topic  to  the  books  of  John 
and  Charles  S.  Tomes,  Baume,  Farrar,  Kingsley,  and  Talbot. 

In  rare  cases  teeth,  usually  fully  developed,  are  found  in  the 
antrum,  in  the  nasal  ca^^ties,  and  under  the  skin  on  almost  any 
part  of  the  face. 

In  conclusion,  I  wish  to  mention  that  several  cases  of  absolute 
absence  of  both  temporary  and  permanent  teeth  are  on  record 
in  the  literature,  so-called  "  edentuli." 


LITERATURE. 


The  author  is  sensible  that  the  references  to  the  literature  of  the  subjects 
treated  in  this  hook  are  incomplete,  but  he  nevertheless  cherishes  the  hope  that 
his  earnest  etforts  have  added  real  value  to  the  catalogue  of  authors  who  have 
contributed  to  the  general  stock  of  knowledge  in  this  direction,  and  that  the 
labors  of  those  who  delve  in  the  same  field  after  him  will  thus  be  lightened. 

To  avoid  frequent  repetitions  the  standard  works  are  given  first,  as  bearing 
more  or  less  on  every  chapter  of  this  work.  The  remainder  of  the  literature  has 
been  arranged  as  nearly  as  possible  in  the  order  of  the  chapters,  having  been 
collected  from  the  principal  American,  English,  and  German  journals,  as  well 
as  from  the  works  of  Miller,  Arkovy,  and  Schefi". 

J.  Hunter.     The  Nat.  History  of  the  Human  Teeth.     London,  1778. 

M.  Desirabode.     Science  and  Art  of  the  Dentist.     Baltimore,  1847. 

E.  Saunders.  Diseases  and  Operations  on  the  Teeth.  [Am.  Jour,  of  Dent. 
Sci.     1846.) 

J.  Tomes.  A  Course  of  Lectures  on  Dental  Physiology  and  Surgery.  Lon- 
don, 1848. 

J.  Tomes  and  C.  S.  Tomes.  A  System  of  Dental  Surgery.  Philadelphia, 
1873. 

P.  B.  GoDDARD.  The  Anatomy  and  Physiology  of  the  Human  Teeth. 
Philadelphia,  1844. 

J.  V.  Metnitz  und  C.  Wedl.  Atlas  zur  Pathologie  der  Zahne.  Wien, 
1889. 

C.  Gegenbauer.     Lehrbuch  der  Anat.  des  Menschen.     Leipzig,  1889. 

J.  Htrtl.     Lehrbuch  der  Anat.  des  Menschen.     Wien,  1881. 

S.  T.  SOmmering.     Der  Bau  des  Menschl.  Kdrpers.     Frankfurt,  1800. 

A.  Coleman.     Dental  Surgery. 

S.  J.  A.  Salter.     Dental  Pathology  and  Surgery.     London,  1874. 

J.  LiNDERER.  Die  Zahnheilkunde  nach  ihrem  neuesten  Standpunkt.  Erlan- 
gen,  1851. 

—  Meckel.     Tab.  anat.  path      Ease.  III.     Lipsiae,  1812. 

E.  Jessen.     Lehrbuch  der  Praktischen  Zahnheilkunde.     Wien,  1890. 

C.  Demontporcelet  et  E.  Decaudin.  Manuel  d'Anatomie  Dentaire  Hu- 
maine  et  Comparee.  Avec  introduction  par  M.  le  Professeur  P.  Brouardel, 
doyen  de  la  Eaculte  de  Medecine  de  Paris.     1891. 

A.  BuzER.     Handb.  der  Zahnheilk.     Berlin,  1887. 

S.  Strickek.     Manual  of  Histology.     New  York,  1872. 

C.  Wedl.     The  Pathology  of  the  Teeth.     Philadelphia,  1872. 

E.  Owen.     Odontography.     London,  1840-1844. 

L.  S.  Beale.     On  the  Structure   and    GroAvth  of   the  Tissues    and  on    Life. 
London,  1866. 
614 


LITERATURE.  615 

A.  EoTHMAx.  Patho-Histologie  der  Zalmpulpa  und  "Wurzelhaut.  Stuttgart, 
1889. 

J.  ArkOvy.     Diagnostik  der  Zahnkrankheiten.     Stuttgart,  1885. 

H.  Helmkampf.  Diagnose  und  Therapie  der  Erkrankungen  des  ilundes  und 
Kacheus.     Stuttgart,  1886. 

H.  Gray.     Ano^'^^'';" 

n.  Si,iTZMAXJf.    Die  Descriptive  und  Topographisclie  Anatomie.    Wien,  1875. 

E.  Ztjckeekaxdl.  ]S^orniale  und  Pathologisclie  Anatomie  der  Nasenholile. 
Bd.  I  and  II.     Wien  und  Leipzig,  1882  und  1892, 

J.  ScHEFF,  Jr.     Handbuch  der  Zahnheilkunde.     "Wien,  1891. 

J.  E.  Garretson.     a  System  of  Oral  Surgery.     Philadelphia. 

R.  Baume.     Odoutol.  Forschungeu.     Leipzig,  1882. 

L.  Braxdt.     Lehrhuch  d.  Zahnheilk.     Berlin,  1890. 

J    Y.  Elagg.     Dental  Pathology  and  Therapeutics.     Philadelphia,  1872. 

E.  Pakmly.  An  Essay  on  the  Disorders  and  Treatment  of  the  Teeth.  ]S'ew 
York,  1822. 

L.  S.  Parmly.  Lectures  on  the  Xatural  History  of  the  Teeth.  Xew  York, 
1820. 

T.  Bell.  The  Anatomy,  Physiology,  and  Diseases  of  the  Teeth.  Phila- 
delphia, 1837. 

S.  S.  Fitch.     System  of  Dental  Surgery.     New  York,  1829. 

J.  Fox.     The  IS'atural  History  and  Diseases  of  the  Teeth.     London,  1814. 

D.  TT.  Jacobsox.  Outlines  of  the  Anatomy  and  Physiology  of  the  Teeth. 
Edinburgh,  1834. 

L.  KoECKER.     Principles  of  Dental  Surgery.     Baltimore,  1842, 

C.  A.  Harris.  Dissertation  on  the  Diseases  of  the  Maxillary  Sinus.  Phila- 
delphia, 1843. 

A.  Nasmyth.  Eesearches  on  the  Development,  Structure,  and  Diseases  of 
the  Teeth.     1849. 

P.  F.  Blaxdix.     Anatomy  of  the  Dental  System.     Baltimore,  1845. 

G.  Carabelli.     Systemisches  Handbuch  der  Zahnheilkunde.     Wien,  1844. 

J.  Fox  and  C.  A  Harris.  The  Natural  History  and  Diseases  of  the  Human 
Teeth.     Philadelphia,  1846. 

C.  0.  CoxE.  An  Essay  on  the  Structure  and  Formation  of  Teeth  in  Man  and 
Yarious  Animals.     Baltimore,  1848. 

T.  Berdmore.  a  Treatise  on  the  Disorders  and  Deformities  of  the  Teeth  and 
Gums.     Baltimore,  1844 

D.  "VY.  JoBSOX.  A  Treatise  on  the  Anatomy  and  Physiology  of  the  Teeth. 
Baltimore,  1844 

C.  A.  Harris.  The  Principles  and  Practice  of  Dental  Surgery.  Phila- 
delphia, 1866. 

E.  Battme.     Lehrbuch  der  Zahnheilkunde.     Leipzig,  1885. 
J.  ScHEFF.     Lehrbuch  der  Zahnheilkunde.     Wien,  1884. 

J.  E.  Metxitz      Lehrbuch  der  Zahnheilkunde.     Wien,  1891. 
ISr.  W.  KiXGSLEY'.     A  Treatise  on  Oral  Deformities.     New  York,  1880. 
M.  H.  Cryer.     (American  System  of  Dentistry  )     Philadelphia,  1886. 
A.  P.  Brubaker.     (American  System  of  Dentistry.)     Philadelphia,  1886. 
J.   L.  WoRTMAX.     (American  System  of  Dentistry.)     Philadelphia,  1886. 
W.  X.  SuDDTJTH.    Embryology,  etc.    (American  System  of  Dentistry.)    Phila- 
delphia, 1886. 

C.  S.  Tomes.     A  Manual  of  Dental  Anatomy.     Philadelphia,  1876. 


616  LITERATURE. 

H.  Jt7DD.  An  Anatomical  Description  of  the  Permanent  Teeth.  St.  Louis^ 
1877. 

P.  Pfeffekmaxx.  Passliche  Darstellung  der  Gesamten  Zahnheilkunde. 
Stuttgart,  1864. 

M.  Heidee  und  C.  "Wedl.  Atlas  zur  Pathologic  der  Ziihne.  Zeichnungen 
von  C.  Heitzmann.     Leipzig,  1869. 

E.  MttHLEEiTER.     Anatomie  des  Mensclilichen  GeMsses.     Leipzig,  1891. 

P.  ScHECH.     Die  Xrankheiten  der  Mundhohle,  etc.     Wien,  1892. 

A.  S.  L^XDEEWOOD.     Aids  to  Dental  Histology.     London,  1892. 

C.  Eescheeitee.     Zur  Morphologie  des  Sinus  Maxillaris.     Stuttgart,  1878. 

J.  Paeeeidt.     Zahnheilkunde.     Leipzig,  1891. 

K.  Spieltogel.  Die  Ursachen  der  Zahnkrankheiten ;  ihre  Polgen,  Verhii- 
tung,  und  Behandlung,  etc.     Landsberg  a.  d.  W.,  1891. 

M.  Small  and  J.  P.  Colter.  Diseases  and  Injuries  of  the  Teeth.  London, 
1893. 

L.  HoLLAEXDER.     Das  Fiilleu  der  Zahne.     Leipzig,  1885. 

J.  Taft.     Operative  Dentistry.     Philadelphia,  1859. 

A.  "WiTZEL.     Deutsche  Zahnheilkunde  in  Vortragen      Hagen,  1886. 

A.  "WiTZEL.  Die  Antiseptische  Behandlung  der  Pulpakrankheiten.  Berlin, 
1879. 

A.  WiTZEL.  Compendium  der  Pathologie  vmd  Therapie  der  Pulpakrank- 
heiten des  Zahns.     Hagen  in  W.,  1886. 

H.  Feet.     Compendium  of  Histology.     ]S^ew  York,  1876. 

L.  Eanviee.     Technisches  Lehrhuch  der  Histologic.     Leipzig,  1877. 

0.  H.  Stockwell.  The  Microscopic  Structure  of  a  Human  Tooth.  Ann 
Arbor,  1887. 

CHAPTERS   I.    II. 

J.  B.  Sutton.  Development  of  the  Lower  Jaw.  [Dental  Cosmos.  Vol, 
XXY.) 

C.  Heitzmank  and  P.  Abbott.  Senile  Atrophy  of  the  Upper  Jaw.  [Dental 
Cosmos.     Vol.  XXXIV.) 

J.Wolff.     tJber  das  Wachsthum  des  TJnterkiefers.    [Vir  chow' s  Arch.     1888.) 

H.  Welker.  Untersuchungen  iiber  Bau  und  Wachsthum  des  Menschlichen 
Schadels.     Leipzig,  1862. 

G.  EuGE.  Beitrage  zum  Wachsthum  des  Menschlichen  Unterkiefers.  Berlin, 
1876. 

P.  Steassmaxx.  ISTonuuU.  observ.  de  ossium.  increment,  pertinentes.  Diss 
inaug.     Berolini,  1862. 

G.  M.  HuMPHET.  On  the  Growth  of  the  Jaws.  (Trans  of  the  Cambridge 
Philos.  Soc.     Vol.  XI. ) 

0.  ZsiGMONDT.  tJber  die  Veraenderungeu  des  Zahnbogens  bei  der  Zweiten 
Dentition.      [Arch.  f.  Anat.  und  Physiol       1890.) 

CHAPTERS   III,    IV. 

E:  MttHLEEiTER.  tlber  Maximal-  und  Minimalgrossen  der  Zahne.  [Deut. 
Vier.  Jahrsch.  f.  Zahnheilk.     1874.) 

J.  S.  Latimer.  Anatomy  and  Physiology  of  the  Teeth.  [Dental  Cosmos. 
Vol.  VIII.) 

W.  H.  Elowee.  On  the  Size  of  the  Teeth  as  a  Character  of  Race.  {Dental 
Cosmos.     Vol.  XXVII.) 


LITERATURE,  617 

J.  PoHLMAX.     Human.  Teeth  and  Evolution.     {Dental  Cosmos.    Vol.  XXIX.) 

E.  T.  Staer  and  F.  L.  Hise.  Typical  Tooth  Forms.  {Denial  Cosmos.  Vol. 
XXXI  ) 

31.  A.  BuRCH.  The  Growth  and  Development  of  the  Jaw.  California  State 
Odont.  Soc,  1885 

Fr  Blaxdix.  Historische  Skizze  iiber  die  Anatomie  der  Zahne.  {Der  Zahnarzt. 
1848.) 

Fr.  Blaxdin.  Uber  den  Bau  und  die  Organisation  der  3Ienschl.  Zahne.  {Der 
Zahnarzt.      1848  ) 

H    Alle>-.     The  Facial  Region.     {Dental  Cosmos      Vol.  XIV.) 

A.  H.  Thompson.  The  Homology  of  the  Dental  Tissues,  etc.  {Dental  Cosynos. 
Vol.  XIX.) 

C.  X.  Peirce.  The  Development  of  the  Teeth,  etc,  {Dental  Cosmos.  Vol. 
XIX.) 

J.  W.  "Wick.     A  Reunited  Tooth.     {Archives  of  Dentistry.     1887.) 

M.  Heider  Anatomische  Beohachtungen  iiber  die  Zahne  und  Zahnreihen. 
{Deut.  Vier.  .Jahrsch.f.  Zahnheilk.     1868.) 

E.  ScHWARTZKOPF.  Die  Zahne  bei  Zwergen.  {Deut.  Monatssch.f.  Zahnheilk. 
1884.) 

J.  Parreidt.  Uber  die  Bezahnung  bei  ilenschen  mit  abnormer  Beharung. 
{Deut.Monatsschr   f.  Zahnheilk.     1886  ) 

J.  Parreidt.  Sind  die  mittleren  oberen  Schneideziihne  bei  der  Frau  absolut 
oder  verhaltnissmassig  breiter  als  beim  Manne.  etc.  {Deut.  Monatsschr.  f.  Zahn- 
heilk.    1886  ) 

F.  BuscH.  Die  tjberzahl  und  Unterzahl  in  den  Zahnen  des  Menschlichen 
Grebisses,  etc.     {Deut   Monatsschr.  f.  Zahnheilk.     1887.) 

H.  Jtjdd.     The  Deciduous  Teeth.     {Missouri  Dental  Journal.     1874.) 

J.  Parreidt.  Die  Ui-sachen  der  Missverhaltnisse  zwischen  den  Grossen  der 
Kiefer  und  denjenigen  der  Ziihne.     {Deut.  Monatsschr.  f.  Zahnheilk.     1884  ) 

E.  MiJHLREiTER.     Anat.  des  Menschl.  Gebisses.     Leipzig,  1870. 

E.  ZrcKERKA>-DL.     Uber  rudimentarc  Zahne.     {Medicin.  Jahrb.     1885 'i 

H.  Hertz.  Ein  Fall  von  geheilter  Zahnfraetiir  mit  nachfolgender  abnormer 
Schmelzbildung.     {Virchow's  Arch.     1867.) 

E.  Zxxckerka:n"dl.  Macroscopische  Anatomie  in  Handb.  der  Zahnheilk  .  von 
J.  Scheff,  Jr.     Wien,  1891. 

J.  F.  Etmer.    -Xotes  on  Dental  Anatomy.     London,  1892. 

A.  B.  Salzer.     Die  Milchzahne  in  der  Praxis.     {Odontoskop.     1893.) 

M.  ScHLOSSER.  tjber  die  Deutung  des  3Iilchgebisses.  {Biolog.  Centralbl. 
1890.) 

M.  ScHLOSSER.  Die  Differenzirung  des  Saugethiergebisses  {Biolog.  Centralbl. 
1890.) 

-     "W.  KtJHXTHAL.    Einige  Bemerkungen  iiber  die  Saugethierbezahnung.    {Anat. 
Anzeiger.     1891  ) 

C.  EosE.  iiber  Entstehung  und  Formabanderung  der  Menschlichen  Molaren. 
{Anat.  Anzeiger.     1892.) 

E.  Mahieu.  Contribution  a  Petude  de  la  premiere  dentition.  (These.)  Pari-s. 
1894. 

CHAPTERS    V,   VI. 

T.  L.  James.     Pulp-Canals  of  Human  Teeth.     {Dental  Revieic.     1890.) 
C.  E.  Latimer.     Pulp-Cavities.     {Dental  Co.rmos.     Vol.  VI.) 


618  LITERATURE. 

"VV.  G.  A.  BoxAViLL.  Articulation  and  Articulators.  (Trans.  Am.  Dent.  Ass. 
1865.) 

W.  Gr.  A.  Box-iviLL.  What  has  Dentistry  to  Demonstrate  against  the  Hypoth- 
esis   of  Organic  Evolution  ?     [Dental  Cosmos.     Vol.  XXXV. ) 

I.  B.  Datexpoet.     Articulation  of  the  Teeth.     {Intern.  Dejit.  Jour.     1892.) 

I.  B.  Davexpokt.  The  Significance  of  the  ISTatural  Form  and  Arrangement 
of  the  Dental  Arch,  etc.     {Dental  Cosmos.     Vol.  XXIX  ) 

L  Waexekros.  Die  Pixirung  der  Bewegungen  des  Unterkiefeis  beim  Kauakt. 
Berlin,  1892. 

CHAPTEES    VIII,    IX. 

C.  Havers.     Osteologia  Nova      London,  1691. 
E.  JSTesbitt.     Human  Osteogeny.     London,  1731. 

—  Dt'HAMEL.     Memoires  de  I'Acad.  Paris,  1742. 

J.  HrxTER.  Experiments  and  Observations  on  the  Growth  of  Bone.  London, 
1798. 

J.  HowsHiP.  Microscopic    Observations   on    the   Structure  of  Bone.     {Med. 

Chlrur.  Trans.  London,  1816.) 

J.  MuLLER.  {Mailer's  Arch.     1836.) 

—  Lessixg.  Uber  ein  plasmatisches  Gefass-System  in  alien  Geweben,  insbe- 
sondere  in  Knochen  und  Zahnen.     Hamburg,  1846. 

E.  ViRCHow,     Wurzburger  Verhandlungen.     1850. 

E.  aSTETJMAX".  Beitrage  zur  Kenntniss  des  normalen  Zahnbeins  und  der 
Knochengewebe.     KOnigsberg,  1863. 

A.  KOlliker.     3Iikroskopische  Anatomic.     1850. 

—  De  Morgax.  Observations  on  the  Structure  and  Development  of  Bone. 
1852,  and  Philosojjh.  Trans.,  1853. 

H.  MtJLLER      {Zeitschr.f.Wiss.  Zool.     Bd.  IX.     1858.) 

E.  Li.XG.  TJntersuchungen  iiber  die  ersten  Stadien  der  Knochenentziindung. 
(  Wiener  Med.  Jahrh.     1871. ) 

—  EuGE.     {Virchoic's  Arch.     Bd.  XLIX.) 
J.  Wolff.     {Virchow's  Arch.     BdL.) 

iSr.  LiEBERKtiHX.     {Sitzungsber.  der  Marburger  Gesells.     1872.) 

—  Strelzoff.     L^ntersuchungen  aus  dem  Pathol.  Instit   zu  Zurich      1878. 

—  Steudexer.  Beitrage  zu  der  Lehre  von  der  Knochenentwicklung  (Abh. 
der  Naturf.  Ges.  zu  Halle.     1875.) 

L.  Beale.  The  Structure  of  the  Simple  Tissues  of  the  Human  Body.  London, 
1860. 

M.  ScHULTZE.     Eeichert  und  Du  Bois  Eeymond's  Arch.     1861. 

Th.  Schwaxx.     Microskopische  Untereuchungen.     Berlin,  1839. 

J.  Hexle.     Allgemeine  Anat.     1845. 

M.  Schultze.     {Centralbl.  f.  d.  Med.  Wiss.     1864.) 

A.  Spixa.  IJber  die  Saftbahnen  des  hyalinen  Knorpels.  {Sitzimgsb.  der  Wiener 
Akad.  d.   Wiss.     1879.) 

S.  Stricker.  Mittheilungen  liber  Zellen  und  Grundsubstanzen.  {Wiener  Med. 
Jahrh.     1880.) 

A   EoLLET.     S.  Stricker \s  Manual  of  Histology.     1872. 

P.  V.  Eecklixghal^sex.     Wanderzellen.     {Virchow' s  Arch.     Bd.  XXVIII.) 

C    ToLDT.     Lehrbuch  der  GeAvebelehre.     1877. 

L  Eaxvier.  Des  Lesions  du  Tissu  Cellulaire  lache  dans  I'Oedeme.  {Comptes 
Rend  I,  s.      1871.) 


LITERATURE.  619 

W.  Hassloch.     Cornea.     {Arch,  of  Ophthal.  Otol.     Yol.  VII.     1878.) 
W.  Waldeyer.     Cornea.     (In  Graefe  Saemisoli's  Handb.     1874.) 

—  DoNDERS.     {ZeUsch):  f.  Wiss.  Zool.     Bd.  III.) 

—  FuRSTEXBERG.     [Midler' s  Arch.     1857.) 
E.  ViRCHOw.     Cellularpathologie.     1858. 

E.  Heidexhaix.     Studien  des  Physiol.  lustit.  zu  Breslau.     1863. 

L.  Elsberg.  Contributions  to  the  Normal  and  Pathological  Histology  of  the 
Cartilages  of  the  Larynx.  [Arch,  of  Laryngology.,  Vol.  II  ,  1881,  where  a  good 
■collection  of  the  literature  on  cartilage-tissue  will  be  found.) 

P.T.Smith      Cell-Metamoi-phosis.     {Iniern.  Dent.  Jour.     1893.) 

E.  E.  Warxer      Products  of  the  Epiblast      [Dental  Cosmos.     Vol.  XXX.) 

W.  H.  Atkixsox.     Epithelium.     [Trans.  X.  Y.  Odontol.  Soc.     1877.) 

Th.  Schwax'X'.  Untei-suchungen  iiber  die  Ubereinstimmung  in  der  Structur 
und  dem  Wachsthum  der  Thiere  und  Pflanzen.     Berlin,  1839. 

M.  ScHULTZE.  IJber  Muskelkorperchen  und  das  was  man  eine  Zelle  zu  nennen 
habe.     [Muller's  Arch.     1861.) 

E.  BRtJCKE.  Die  Elementarorganismen.  [Sltzungsber.  der  Wiener  Akudem.  der 
Wiss.     1861.) 

S.  Stricker.     Handbuch  der  Lehre  von  den  Geweben.     1868. 

Jul.  Cohx^heim.  tjber  die  Endigungen  der  sensiblen  Xerven  in  der  Horn- 
haut.     [Virchow's  Ai'ch.     1867.) 

—  Gegexbatier.     [Jenaische  Zeitschr.  f.  Med.  und  Naturwiss.     1864.) 
E.  ViRCHOW.     Die  Celhilarpathologie.     1871. 

K.  KOsTER.  tJber  die  feine  Structur  der  Meuschlichen  ISTabelschnur.  Wiirzburg. 
1868. 

r.  T.  Eecklixghavsex'.  Die  Ljinphgefasse  und  ihre  Beziehung  zum  Binde- 
gewebe.     Berlin,  1862. 

Th.  Billroth.     [Arch.f.  Klmische  Chirurgle.     Bd.  XL) 

"W.  Kraxjse.  IJber  den  Bau  der  quergestreiften  Muskelfaser.  (Zeitschr.  f.  rai. 
Med.     1868.) 

V.  Hex'sex*.  Uber  ein  neues  Structurverhaltniss  der  quergestreiften  Muskel- 
faser.     (Arbeiten  des  Kieler  Physiol.  Instit.     1868.) 

T.  W.  Ex^'gelmaxx'.  Microsk  Untersuchungen  iiber  die  quergestreiften  Muskel- 
.substance.     [Pfliiger's  Arch.     1873.) 

E.  Brijcke.  Untei-s.  liber  den  Bau  der  Muskelfasern,  etc.  [Denkschr.d.  Wiener 
Akad.  der  Wiss.     Bd.  XV.) 

L.  Elsberg.     [Virchoio' s  Arch.     Bd   XXXVIII.) 

L.  UxGER.  Untersuchungen  liber  die  Entwicklung  der  centralen  ISTerven- 
gewebe.     [Sitzungsber.  der  Wiener  Akad.  der  Wiss.     1879.) 

C.  Heitzmax"X'.  Untersuch.  iiber  das  Protoplasma.  [Sitzungsber.  der  Akad. 
■der  Wiss.  in  Wien.     1873.) 

C.  HEiTZMAXTf.     Studien  am  Knochen  und  Knorpel.     [Med.  Jahrb.     1872.) 

V.  T.  Ebxer.  IJber  den  feinen  Bau  der  Knochensubstanz.  [Sitzungsber.  der 
Wiener.  Akad.  der  Wiss.     1875.) 

C.  Laxger.  tJber  das  Gefass-System  der  Eohrenknochen.  [Denkschr.  der 
Wiener.  Akad.  der  Wiss      1875.) 

C.  Laxger.  tJber  die  Blutgefasse  der  Knochen  des  Schadeldaches.  [Denk- 
schr. der  Wiener  Akad.  d.   Wiss.     1879.) 

M.  Kassowitz.     Die  Normale  Ossification.     [Wiener  Med.  Jahrb.     1879.) 

C.  Heitzmaxx.     Microsc.  Morphology.     New  York,  1883. 

—  Dry.sdale.     The  Protoplasmic  Theory  of  Life.     London,  1874. 


620  LITERATURE.". 

J.  Fletchek.     Eudiments  of  Physiology.     Edinburgh,  1835. 

Feed.  Cohx.  Xachtrage  zur  Xaturgeschichte  des  Protococcus  pluvialis. 
(Xova  acta  Acad.  Leop.  Carol.     Tol.  XXII  ) 

T.  H.  Hl'Xlet.  Eeview  of  the  Cell-Theory.  {Brif.  and  Foreic/n  Medico-Chirurg. 
Review.     1853.) 

L.  Unger.     Anat.  und  Physiol,  der  Pflanzen.     1855. 

M.  ScHL'LTZE.  tjber  innere  Bewegungs-Erscheinungen  bei  Diatomeen. 
{Muller's  Arch.     1858.) 

M.  ScHTJLTZE.     rber  Cornuspira.     [Arch.  f.  Naturgesch.     \WQ.) 

M.  ScHTJLTZE.  Das  Protoplasma  der  Ehizopoden  und  der  Pflanzenzellen. 
Leipzig,  1863. 

Haeckel.     Monographie  der  Eadiolarien.     1862. 

Haeckel.  Uber  den  Sarcodekorper  der  Ehizopoden.  [Zeitschr.  f.  Wiss.. 
Zool.     1865.) 

Haeckel.     Generelle  Morphologic.     Vol.  I.     Pp.  269  and  289. 

Haeckel.  Monographie  der  Moneren.  {Jenaische  Zeitschr.  f.  Med.  und  Naticr- 
wiss.     1868.) 

—  Bastiax.     The  Beginnings  of  Life.     London,  1872. 

C.  Heitzmaxx.     Epithelium  and  Its  Performances.     {Xeic  York  Med.  Jour^ 
1878.) 
C.  EoKiTAxsKT.     Handb.  d.  AUg.  Pathol.  Anat.     1846. 
L.  Eaxviee.     Traite  Technique  d'Histologie.     Paris,  1889. 
A.  KOlliker.     Handbuch  der  Gewebelehre.     Leipzig,  1889. 
C.  Told.     Lehrbuch  der  Ge-^vebelehre.     Stuttgart,  1888. 
0.  Hartwig.  Lehrbuch  der  Entwicklungsgeschichte.     Jena,  1893. 

CHAP  TEES   X-XY. 

—  EusTACH,  1574.     (M.  Pfliiger,  Deut.  Vier.  Jahrschr.  f.  Zahnheilk.     1867.) 

—  Herissaxt,  1745.     (M.  Pfliiger,  Deut.  Vier.  Jahrschr.  f.  Zahnheilk.     18 17.) 
Vox  SwixTOX  und  BRrxxER,  1771.     (M.  Pfliiger,   Deut.   Vier.   Jahrschr.  f. 

Zahnheilk.     1867.) 

K.  Blake,  1780.     (M.  Pfliiger,  Dent.  Vier.  Jahrschr.  f.  Zahnheilk.     1867.) 

—  Delabarre.  1805.  (In  Syst.  Handb.  d.  Zahnheilk.  von  G.  v.  Carabelli.  Wien, 
1844.) 

H.  M.  Hatdex,  1813.     {Am.  Jour,  of  Dent.  Science.     Vol.  I.) 

J.  Pox.     The  Xatm-al  History  and  Diseases  of  the  Teeth.     London,  1814. 

—  Leszai,  in  1830.  (In  Deut.  Vier.  Jahrschr.  f.  Zahnheilk.  1867.  By  M. 
Pfliiger.) 

F.  Aexold.     [Medic.  Chiricrg.  Zeitung.  Insbruck.     1831.) 

Purkix.je  and  Easchkow,  1835.     In  ISTasmyth  Eesearches,  etc.  (1.  c.) 

—  Fraexkel.     De  penitiori  dentium  hum.     Struct.  Diss.  Vratislav.     1835. 
J.  Muller.     {Arch.  f.  Anat.  und  P?iysiol.     1836.) 

A.  Eetzitjs.     {Arch.f.  Anat..  Physiol.,  und  Wiss.  Med.,  Muller's.     1837.) 

T  Bell.  The  Anatomy,  Physiology,  and  Diseases  of  the  Teeth.  Philadelphia, 
1837. 

J.  LiXDERER.     Haudbuch  der  Zahnheilk.     Berlin,  1837. 

A.  Xasmtth.  Eesearches  on  the  Development,  Structure,  and  Diseases  of  the 
Teeth.     London,  1839. 

J.  GooDSiR.     {Edinburgh  Med.  ami  Surg.  Jour.     1839.) 

E.  OwEX.     Odontography.     London,  1840-1845. 


LITERATURE.  621 

C.  A.  Harris.     Ou  the  Yascularitr  of  Dental  Bone.      {Am.  Jour,  of  Dent. 
Science.     1841.) 

J.  B.  Gakiot.     Treatise  on  the  Diseases  of  the  Mouth.     Baltimore,  1843. 

P.  F.  Blaxdixe.     Anat.  of  the  Dental  System.     Baltimore,  1835. 

C.  O.  Co^"E.     Origin,  Development,  and  Eraption  of  the  Teeth.     (Am  Jour,  of 
J)enf.  Sci.     1845.) 

J.  GiBSOX.     (In  Der  Zahnarzi.     1846.     P.  89.) 

J.  LixDERER.    Phvsiologische  und  Pathologische  Untersuchungen  der  Ziihne. 
.{Der  Zahnarzt.     1847.) 

~Si..  Desirabode.     Science  and  Art  of  the  Dentist.     Baltimore,  1847. 

J.  Tomes.     A  Course  of  Lectures  on  Dental  Physiology,  etc.     London.  1848. 

J.  Tomes.     Philosoph.  Transactions.     1849,  185(t,  and  1856. 

K.  Blake.     An  Essay  on  the  Structiire  and  Formation  of  the  Teeth  of  Man 
and  Various  Animals.     Baltimore,  1848. 

M.  JorRDAix      A  Treatise  on  the  Diseases  of  the  Mouth.     Baltimore.  1849. 

Pt.  B.  Todd  and  W.  Bowmax.     Anat.  and  Physiol,  of  Man.     Philadelphia, 
1850. 

A.  Krttkexberg.     [In  Der  Zahnarzt.     1850.     P.  118.) 

J.  X.  CzERMAK.     {Zeit.schr.f.^^3.i.  Zool.     1850.) 

JoHX  Tomes.     The  Structure  and  Development  of  Bone.     {Ain.  Jour,  of  Dent. 
.Sci.     1852.) 

J.  D.  "White.     Anatomy  and  Physiology  of  Dentine.      (Dental  Xews  Letter. 
18.52.) 

H.  "White.     Anatomy  and  Physiology  of  Dentine.     (Atn.  Jour,  of  Dent.  Sci. 
1852.) 

"W.  KoGERS.     tjher  die  Entwicklung  der  Kinnlade  und  der  Zahne.     (Der  Zahn- 
arzt.    1852  and  1858.) 

A.  KoLLiKER.     (Microsk.  Anat.     Bd.  II.     Leipzig.  1852.) 

A.  KoLLiKER.     (Zeitsch.  Wiss.  Zool.     1862.) 

A.  KoLLiKER.     Gewehelehre.     1867. 

A.  KoLLiKER.     Entwicklungsgeschichte  des  Menschen  und  derHoheren  Thiere. 
Leipzig.  1879. 

"W.  T.  Ers-SEL.     An  Essay  on  the  Structure  and  Development  of  the  Dental 
Tissues.     (Am.  Jour,  of  Detit.  Science.     1853.) 

J.  E.  OuDET.     Microskopische  Studien  iiber  die  Zahne.     (Am.  Jour,  of  Dental 
Science.     1854.) 

J.  Lefottlox".     Pathologische  Betrachtungen  iiber  die  Zahne.     (Am.  Jour,  of 
Dental  Science.     1856  and  1857.). 

E.  Lext.     (Zeitschr.f.  Wiss.  Zool.     1855.) 

T.  H.  HrxLET.     (Quart.  Jour,  of  Micro.  Science.     London.   1853.   1854.   and 
1855.) 

—  Haxx'Over.     Die  Entwicklung  und  der  Bau  des  Saugethierzahns.  (Verhandl. 
d.  Kaiserl.  Akad.  d-   Xaturforsch.     1856.) 

J.  Tomes.     On  Certain  Conditions  of  the  Dental  Tissues.     (Am.  Jour,  of  Dent. 
Science.     1856.) 

C.   Johxstox.     Conti-ibutions  to  the  Minute  Anatomy  of   the  Teeth.     (^4???. 
Jour,  of  Dent.  Science.     1857.) 

S.  J.  A.  Salter.     Papei-s  on  Dental  Pathology.     (Am.  Jour,  of  Dent.  Science. 
4857.) 

A.  F.  Talma.     (In  Der  Zahnarzt.     1853.     P.  193.) 

J.  E.  OrDET.     (In  Der  Zahnarzt.     1858.     P.  256.) 


622  LITERATURE. 

M.  Fkanko.     [In  Der  Zahnarzt.     1856.     P.  1.) 

]Sr.  Gtjillot.     (In  Der  Zahnarzt.     1858.     P.  177.) 

Ch.  Kobix  and  E.  Magitot.  {Jour,  de  Physiol,  de  Broivn-Sequard.  1860  and 
1861.)     (English,  Denial  Cosmos.     1861.) 

A.  HOPPE.     {Virchow's  Arch.     1862.) 

L.  S  Beale.  On  the  Structure  and  Growth  of  the  Tissues,  and  on  Life.  London, 
1865. 

G.  Hertz.     {Virchoic's  Arch.     1866.) 

G.  Hertz.     {Virchow' s Arch .     Bd.  XXXYIIL) 

J.  H.  McQuiLLEN.  Microscopy  of  the  Dental  Tissues.  {Dental  Cosmos.  Vol. 
VIL) 

J.  H.  McQriLLEX.  The  Interglobular  Spaces  in  Dentine.  [Dental  Cosmos. 
Vol.  VIII.) 

S.  p.  Cutler.  Microscopy  of  the  Teeth.  {Dental  Cosmos.  Vols.  VIII, 
IX,  and  X.) 

J.  H.  3IcQl'illex.  The  Interglobular  Spaces.  (Trans.  Am.  Dent.  Ass. 
1866.) 

S.  P.  Cutler.     Microscopy  of  the  Teeth.     (Trans.  Am.  Dent.  Ass.     1868) 

"W.  Waldeyer.  Tiber  die  Entwickelung  der  Zahne.  {Kbnigsberger  Med. 
Jahrhucher.     1864.) 

W.  Waldeyer.     (In  S.  Strieker ^s  Manual  of  Histology.     Xew  York,  1872.) 

M.  Peluger.     {Deut.  Vier.  Jahrsehr.f.  Zahnheilk.     1867.     P.  167.) 

E.  F.  Wexzel.     {Arch,  der  Heilk.     1868.     P.  97.) 

G.  G.  Ziegler.     Dental  Tissues.     {Dental  Cosmos.     Vol.  XL) 

J.  Kollmajs'^t.  {Sitzimgsberichte  der  K.  B.  Akadeniie  der  Wiss.  zu  Munchen. 
1869.     P.  162.) 

J.  KoLLMAXX.  {Sitzungsberichte  der  K.  B.  Akademie  der  Wiss.  zu  Mimchen. 
1871.     P.  243.) 

E.  MtJHLREiTER.     {Deut.  Vicr.  Jakrsch.  f.  Zahnheilk.     1868.     P.  168.) 

E.  DuKSY'.  Zur  Entwicklungsgeschichte  des  Kopfes  des  Menschen  und  der 
hoheren  Wirbelthiere.     Tubingen,  1869.     P.  211. 

C.  Tomes,     {quart.  Jour,  of  Micro.  Science.     Vol.  XII.     P.  321.) 

F.  Leydig.     {Arch.  f.  Micro.  Anat.     Bd.  IX.     P.  1.) 

C.  Wedl.     The  Pathology  of  the  Teeth.     Philadelphia,  1872. 

G.  EoLLESTONE.     {Quar.  Jour,  of  Micro.  Science.     London,  1872.     P.  109.) 
J.  F.  Flagg.     {Dental  Cosmos.     Vol.  XIV.     Pp.  580  and  633.) 

J.  KoLLMAXx.     {Zeitschr.f.  Wiss.  Zool.     1873.     P.  354.)    ' 

H.  Sewill.     {Dental  Cosmos.     Vol.  XVII.     P.  658. ) 

—  Heix'cke.     {Zeitschr.f.  Wiss.  Zool.     1873.     P.  495.) 

0.  Hertwig.     {Jenaische  Zeitschr.     1874.     P.  331.) 

H.  Frey.     Grundziige  der  Histologie.     Leipzig,  1885. 

H.  Beales.     a  Study  of  Tooth-Development,  etc.     {Indep.  Pract.     1885.) 

R.  E.  Axdrews.    The  Development  of  the  Teeth.     {Arch,  of  Dentistry.    1885.) 

C.  Tomes.     {Monthly  Micro.  Jour.     1874.     P.  85.) 

C.  Tomes,     [quar.  Jour,  of  Micro.     1874.     P.  44.) 

C.  Legros  and  E.  Magitot.  The  Origin  and  Formation  of  the  Dental  Follicle. 
(English  by  M.  S.  Dean.     Chicago,  1880.) 

A.  v.  Bruxx.     {Gottinger  Nachr.     1875.     P.  626.) 

E.  Baume.     {Deut    Vier.  Jahrseh.  f.  Zahnheilk.     1875.     Pp.  125  and  265.) 

T.  C.  White.  On  Some  Points  in  the  Minute  Anatomy  of  the  Pulps  of  the 
Teeth.     (Trans.  Odont.  Soc   Gr.  Britain.     1870.) 


LITERATURE.  623 

T.  C.  Stellwagen.  Development  of  Cells  of  the  Dental  Pulp  intn  Tubuli. 
{^Dental  Cosmos.     Yol.  XII.) 

G.  B.  Hakrimax.  The  Discoveiy  of  Xerve-Fibers  in  the  Soft  Solids  of  the 
Dentine.     {Dental  Cos)nos.     Vol.  XIII.) 

F.  EBERMAJf.     Zahnbeinnerven.     {Deut.  Vier.  Jahrsch.  f.  Zahnheilk.     1872.) 
R    Bax'ME.     Allgemeinerecheinungen  im  Zahnbein.     [Deut.  Vier.  Jahrschr.  f. 

Zahnheilk.     1873,  1874,  1875.) 

R.  Baixme.  Bemerkimgen  iiber  die  Entwickelung  und  den  Bau  des  Saugethier- 
zahns.     [Deut.  Vier.  Jahrsch.  f.  Zahnheilk.     1875.) 

W.  C.  Barrett.  The  Anatomical  and  Histological  Structure  of  the  Deciduous 
Teeth.     ^Trans.  Dent.  Soc.  of  the  State  of  Xew  York.     1874.) 

C.  S.  Tomes.  Studies  upon  the  Attachment  of  Teeth.  (Trans.  Odont.  Soc. 
Gr.  Britain.     1874.) 

—  HrTCHixsox.  The  Dental  Xerve-Pulp  in  Life  and  in  Death.  (Trans.  Odont. 
Soc.  Gr   Britain.     1875.) 

H.  S.  Chase.     Histology  of  Dentine.     [Missouri  Dent.  Jour.     1875.) 

J.  E.  Cratexs.     Pathology  and  Therapeutics.     [Missotvri  Dent.  Jour.     187G.) 

H.  Jt7DD.  Contribution  to  the  Study  of  the  Dental  Fissiires.  {Missouri  Dent. 
Jour.     1877.) 

C.  F.  W.  BOdecker.  The  Distribution  of  Living  Matter  in  Human  Dentine, 
Cement,  and  Enamel.     [Dental  Cosmos.     1878-1879.) 

C.  F.  W.  BOdecker.  Pericementum  and  Pericementitis.  [Dental  Co.rmos. 
1878-1879.) 

C.  F.  W.  BOdecker.     On  Secondary  Dentine.     [Dental  Cosmos.     Vol.  XXI.) 

D.  C.  HAWXHrRST.  Interglobular  Spaces.  [Dental  and  Oral  Science  Magazine. 
1878.) 

G.  V.  Black.     Microscopy  and  Histology.     [Missouri  Dent.  Jour.     1878.) 
W.  A.  Pease      The  Dental  Pulp.     [Missouri  Dent.  Jour.     1878.) 

G.  V.  Black.     The  Odontoblasts.     (Trans.  Am.  Dent.  Ass.     1878.) 

W.  Hailes.     Sections  and  Section-Cutting.     [Am.  Jour,  of  Insanity.     1879.) 

F.  Abbott.  The  Minute  Anatomy  of  Dentine  and  Enamel.  [Dental  Cos'rnos. 
Vol.  XXI.) 

C.  S.  Tomes.  On  the  Development  of  the  Teeth.  (Philos.  Trans  ,  Vol. 
CLXV.,  Proceedings  of  the  Eoyal  Society,  Vol  XXIII. ,  and  Monthly  Micro  Jour  . 
Vol.  XIV.) 

T.  H.  McGiLLAVRY.  tJber  die  Schneidezahne  von  Mus  decumanus.  (Verhandl. 
Med.  d.  K.  Akd.  at  Amsterdam.     2  Pv  ,  IX.) 

C.  S.  Tomes.  On  the  Development  of  Teeth.  [Quar.  Jour,  of  Micro.  Sci. 
1876.) 

J.  ArkOty.  On  the  Developmeiat  of  Dentine.  (Trans.  Odont.  Soc.  Gr. 
Britain.     1876.) 

— •  Tatjber  Existance  de  I'email  sur  les  dents  de  laits  du  Tatusia  peba.  [Jour, 
de  Zool.     1877.) 

C.  S.  Tomes.  On  Some  Forms  of  Dentine  Calcification,  with  Notes  on  their 
Bearing  on  Dental  Pathology.     (Trans.  Odont.  Soc.  Gr.  Britain.     1877.) 

C.  S.  Tomes.  On  the  Structure  of  Vaso-Dentine.  (Philos.  Trans.,  Proc  of 
the  Eoyal  Society.     1878.) 

C.  Aeby.  Architektur  unvollkommen  getheilter  Zahnwurzeln.  [Arch.  f.  Mien.'. 
Anat.     1878.) 

Ch.  Legros  et  E.  Magitot.  Moi^jhologie  du  follicule  dentaire  chez  les  ver- 
tebres.     [Jour,  de  VAnat.  et  de  la  Physiol.     1879.) 


624  LITERATURE. 

—  Boas.     Die  Zahne  der  Scaroiden.     {Zeitschr.  f.  Wiss.  Zool.     1879.) 

E.  Kleiis-  and  E.  Noble.     Atlas  of  Histology.     London,  1880. 

A.  DE  Sarran.  Yaisseaux  sanguines  des  racines  dentaires.  [Gaz.  Med.  de 
Paris.     1880.) 

C.  W.  DxjKX.  Abstract  of  "A  Study  on  Diseases  of  the  Teeth  "  (Trans. 
Odont.  Soc.  Gr.  Britain.     1881.) 

J.  ArkOvy.     Formation  of  Dentine.     (Trans.  Odont.  Soc   Gr.  Britain.    1880.) 

T.  Gaddes.  Dental  Anatomy  and  Physiology.  (Trans.  Odont.  Soc.  Gr. 
Britain.     1881.) 

A.  J.  DoTJDS.  Pathology  of  the  Osseous  Structiu-e  of  the  Teeth.  {Missouri 
Dent.  Jour.     1881.) 

E.  E,.  Andrews.  Eormation  of  Matrix  of  Dentine.  [New  England  Journal  of 
Dentistry.     1883.) 

C.  Matr.  What  is  the  Vitality  of  a  Tooth  ?  [New  England  Journal  of  Den- 
tistry.    1883.) 

F.  Abbott.  Minute  Anatomy  of  the  Human  Tooth.  (Trans,  of  the  Dent. 
Soc.  of  the  State  of  New  York.     1882.) 

C.  F.  W.  BOdecker  The  Minute  Anatomy,  Physiology,  Pathology,  and 
Therapeutics  of  the  Dental  Pulp.     {Dental  Cosmos.     Yol.  XXI Y.) 

J.  B.  Sutton.  Development  of  the  Inferior  Maxilla.  (Trans.  Odont.  Soc. 
Gr.  Britain.     1882.) 

J.  ArkOvy.  Investigations  into  the  Mode  of  Development  of  Odontoma  In- 
ternum Liberum.      {Monthly  Review  of  Dental  Surgery.      1883.) 

C.  S.  Tomes.  On  Some  Scientific  Problems  of  Dental  Surgery.  {Monthly 
Jieview  of  De7ital  Surgery.     1883.) 

F.  Harrison.  Notes  on  the  Alveolo-Dental  Membrane.  {British  Journal  of 
Dental  Science.      1 884  ) 

C.  S.  Tomes.  Note  upon  the  Eeformation  of  Bone.  {Monthly  Review  of 
Dental  Surgery .     1885.) 

F.  Harrison.  Preparing  Tissues  for  Microscopical  Examination.  {Monthly 
Review  of  Dental  Surgery.     1885.) 

W.  X  Sudduth  On  Some  of  the  Pathological  Conditions  Found  in  Dentine 
and  Ivory.     {Dental  Cosmos.     Yol.  XXIX.) 

F.  Abbott.     Teeth  of  Babbits.     {Dental  Cosmos.     Yol.  XXIX.) 

T.  L.  Buckingham.     (Trans   New  York  Odont.  Society,  April  20,  1880.) 

L.  Loewe.  Beitrage  zur  Kenntniss  des  Zahns,  etc.  {Arch.  f.  Micro.  Anat. 
1881.) 

A.  Sternfeld.  Uber  die  Structur  des  Hechtzahnes,  etc.  {Arch.  f.  Micro. 
Anat.     1881.) 

C.  Benda  Die  Dentinbildung  in  den  Hautzahnen  der  Selachier.  {Arch, 
f.  Micro   Anat.     1881.) 

K,  Mathes.     {Dei/t    Vier.  Jahrsch  f.  Zahnheilk.     1881.     P.  252.) 

C.  Legros  et  E.  Magitot.  Contribution  a  I'etude  des  dents.  III.  Developm. 
de  I'organe  dentaire  chez  les-mammiferes.  {Jour  de  I' Anat.  et  de  la  Phys.  17 
annee.     l!-'81.) 

C.  Sihler  Notes  on  the  Formation  of  Dentine  and  of  Osseous  Tissue.  (Stud. 
Biol.  Laborat   Johns  Hopkins  Univ       1881.) 

G.  Annell.  Beitrage  zur  Kenntniss  der  Zahnbildenden  Gewebe,  etc.  Biol. 
Unters  von.  G.  Eetzius.     Stockholm,  1882. 

R    Baume.     Odontologische  Forschungen.     Leipzig,  1882. 

J.  E.  Garretson.     {New  England  Journal  of  Dentistry.     1883.     P.  369.) 


LITERATURE.  625 

—  Wallauer     Ein  Zahnschlitf.    [Dent.  Monatsschr   f.  Zahnheilkunde.    1884) 
P.  Nepper.    Kecherches  sur  la  structure  at  la  genese  de  I'ivoire     [Annales  de  la 

Sci.  de  Med.  de  arand.     1884.) 

—  PoucHET  et  Chabry.  Contributions  a  liodontologie  de  mammiferes.  {Jour, 
de  I'Anat.  et  de  la  Physiol.     1884.) 

O.  Walkhoff.  Microskopische  Untersuchungen  iiber  Pathologische  Veran- 
derungen  des  Dentins.     [DfJit.  Monatsschr.  f.  Zahnheilk      1885) 

M.  MoRGEisrsTERN^.  Meine  Methode  ZalinschlifFe  herzustellen  {Deut.  Monats- 
schr f.  Zahtih eilk.      1885.) 

jM.  Morgensterx.  Untersuchungen  iiber  den  Ursprung  der  bleibenden  Zahne. 
{Deut.  Monatssch.f.  Zuhnhe'dk.      1886.) 

W.  X.  Sttdduth.  Dento-Embryonal  Histology  and  Technology.  {Dental 
Cosmos.     Vol.  XX YI.) 

"W.  X.  SuDDUTH.  The  Embryonic  Malpighian  Layer.  {Dental  Cosinos.  Vol. 
XXVI.) 

O.  Walkhoff.  Beitrag  zur  Lehre  von  den  Contourlinien  und  zur  Physiologie 
des  Zahnbeins.     {Deut.  Monatssch  f.  Zakmheilk.     1885.) 

—  Malassez.    Laboratoire  d'histologie  de  France     Traveaux  de  I'annee  1885. 
J.  L.  "Williams.     On  Certain  Disputed  Points  in  the  Development  and  His- 
tology of  the  Teeth.     {Dental  Cosmos.     Vol   XXVI.) 

J.  L  Williams.  Embiyology  :  With  Special  Keference  to  the  Development 
of  the  Teeth  and  Contiguous  Parts      {Dental  Cosmos.     Vol.  XXVI.) 

J.  L  Williams.  A  Critical  Essay  on  the  Development  and  Minute  Anatomy 
of  the  Teeth,  etc.     {Dental  Cosmos.     Vol   XXVIII.) 

E.  E.  Andrews.  The  Development  of  Enamel.  {Dental  Cosmos.  Vol. 
XXXIII.) 

E.E.Andrews     Growth  of  the  Cementum.    {Dental  Cos^nos.    Vol.  XXXIII.) 

E.  E.  Andrews.  A  Contribution  to  the  Study  of  the  Development  of  the 
Enamel.     (Dental  Cosmos.     Vol.  XXXV.) 

Gr.  S.  Allan.     Enamel  and  Dentine,  etc.     {Dental  Cosmos.     Vol.  XXIX.) 

—  Williamson.  United  Fracture  of  Tooth-Eoots.  {Dental  Cosmos.  Vol. 
XXX.) 

F.Abbott.     Annual  Address.     (Trans.  Am.  Dent.  Ass.     1888.) 
F    J    Bennet.     Certain   Points   Connected   with   the   Structure   of   Dentine. 
(Trans   Odont.  Soc.  Gr.  Britain.     1888.) 

J.  H.  Mummery.  Notes  on  the  Preparation  of  Microscopical  Sections  of 
Teeth  and  Bone.     (Trans.  Odont.  Soc.  Gr.  Britain.     1889.) 

T.  C.  White  and  J.  B   Sutton.     Observations  on  the  Structure  and  Develop- 
ment of  Ovarian  Teeth.     (Trans.  Odont.  Soc.  Gr.  Britain.      1889.) 
E.  D.  Swain.     Embryology.     {Dental  Review.     1888  ) 
G.  S    Allan.     The  Ameloblasts.     (Internat.  Dent.  Jour.     1889.) 
E.  E.  Andrews.      The   Borderland   of    Calcification.     {Internat.    Dent.   Jour. 
1889.) 

G.  H.  McCausey.  The  Eelation  of  the  Tooth-Pulp,  etc.  {Internat  Dent. 
Jour.      1890.) 

P.  Canalis.  SuUo  sviluppo  dei  denti  nei  mammiferi.  {Atiatom.  Anzeiger. 
1886.     P.  187.) 

—  Debierre  et  Pravaz.  Contribution  a  Todontologie.  {Arch,  de  Physio. 
1886.) 

A.  Brunn.  tjber  die  Ausdehnung  des  Schmelzorgans,  etc.  {Arch.  f.  Micro. 
Anat.     1886  ) 

41 


626  LITERATURE. 

R.K.Andrews.    The  Origin  of  the  Dental  Fibers.    {Arch.ofDeniistry.    1887) 

L.  A.  Weil.  Zur  Histologie  der  Zahnpulpa.  {Deid.  Monatssch.  f.  Zahnheilk. 
1887.) 

O.  Walkhoff.  Die  Xonnale  Entwicklung  unci  die  Physiologie  des  Zahnbeins, 
in  den  verschiedenen  Altersperioden  des  Menschen.  [Deut.  Monatssch.  f.  Zahnheilk. 
1887.) 

Gr.  Spee.  tjber  die  ersten  Yorgange  der  Ablagerung  des  Zahnschmelzes.  [Anat. 
Anzeiger.     1887.) 

—  Malassez.  Sur  la  structure  du  gubernaculum  dentis  et  la  theorie  paraden- 
taire.     {Coynpt.  rend,  de  la  Soc.iete  de  Biologie      1887  and  1888  ) 

A.  Eterxod.  Des  lois  mathematiques  et  mecaniques  dans  la  distribution  des 
prismes  de  Teniail.  [Rev.  et  Arch  Suisses  d' Odontologie,  I  annee,  'No.  9.  Geneve, 
1887.) 

F.  Abbott.  Odontoblasts  in  their  Relation  to  Developing  Dentine.  [Dental 
Cosmos.     Vol.  XXX.) 

F.  J.  Bennett.     The  Structure  of  Dentine.     [The  Lancet.     1888.) 

A.  Y.  Brunn.     tiber  die  Menibrana  Praeformativa,  etc      {Anat.  Anz.     1888.) 

R.  R.  Andrews.  The  Pits  and  Fissures  of  the  Enamel.  [Dental  Cos7nos. 
Voh  XXX.) 

R.  R.  Andrews.  The  Development  of  the  Teeth.  (Trans  N.  Y.  Odont.  Soc 
1888.) 

J.  ScHAFEER.  Die  Yerknocherung  des  Unterkiefei-s  und  die  Metaplasiefrage. 
[Arch.f.  Micro.  Anat.     1888.) 

L.  Schmidt.  Structurverliiiltnisse  eines  Zahnrudimentes.  [Deut  Monatssch./. 
Zahnheilk.      1889.) 

F.  Abbott.     Growth  of  Enamel      [Dental  Cosmos-     Yol   XXI.) 
.F.  Rotter.     Tiber  Entwicklung  und  "VYachsthum  der  Schneidezahne  bei  Mus 
musculus.     [Morph.  Jahrb.     1889  ) 

F.  J.  Bennett.  Certain  Points  Connected  with  the  Structure  of  Dentine 
[Am.  Journal  of  Dental  Scioice.     \SB9  ) 

A.  KOlliker.     Handbuch  der  Gewebelehre      Leipzig,  1889. 

C.  S.  Tomes.     A  Manual  of  Dental  Anatomy.     London,  1889. 

L.  Schmidt.  Beitrag  zur  Histologie  der  Knochen  und  Ziihne  in  den  Der- 
moidcysten  der  Ovarien      [Dent   Monat.^.^ch.  f  Zahnheilk.     1890.) 

F.  ROtter.  Tiber  die  vergleichende  Entwicklungs-  und  Wachsthums-Ge- 
schichte  der  Zahne.     [Deut.  Monatssch.  f.  Zahnheilk      1 890  ) 

Y.  V.  Ebner.  Streitige  Fragen  iiber  den  Bau  des  Zahnschmelzes  [Sitzungsher . 
der  K.  Almd.  der  Wiss.     Wien,  1  BiiO. ) 

O    Hertwig.     Entwickelungsgeschichte      Sd  edition 

J  ScHAFFER.  Yerhalten  fossiler  Zahne  in  polai-isirtem  Licht.  [Sitznngsher. 
der  K  Akad.  der  Wiss      Wien,  1891  ) 

A.  CoLLAUD.  Etude  sur  le  ligament  alveolo-dentaire  [Internat  Monatssch. 
f  Anat.  mid  Physio       1890  ) 

M.  MoRGENSTERN.  Entwickluugsgeschichte  der  Ziihne,  in  Handbuch  der 
Zahnheilk.  von  J.  Scheff,  Jr.     Wien,  1891. 

Y.  V.  Ebner  Histologie  def  Zahne.  Handbuch  der  Zahnheilk  von  J.  Scheff, 
Jr      Wien,  1891. 

Iv  RO.SE  Tiber  die  Zahnentwicklung  der  1-leptilien  [Deut  Monatssch.  f 
Zahnheilk.     1 892  ) 

K.  Rose.  Uber  die  EntAvicklung  der  Ziihne  des  Men.schen.  [Arch.f.  Micro. 
Anat.     1891.) 


LITERATURE.  627 

K.  Rose.  tJber die  Entwicklung  des  Menschlichen  Gebisses.  \Verh.  d.  Dent, 
bdont.  Gesell.     Bd.  III.) 

K.  Rose.  Modelle  zur  Demonstration  der  Entwiekkuig  dev  Ziilme  des  Men- 
schen      {Vo-h.  d-  Dnit   Odont.  Gesell.     Bd.  lY.) 

K.  ROsE.  Uber  die  Sclimelzlosen  Zahnrudimente  des  Menschen.  {Verh.  d. 
Dent.  Odont.  Gesell.     Bd.  lY.) 

K.  ROsE.  Contributions  to  the  Histogeny  and  Histology  of  tlie  Bony  and 
Dental  Tissues.     [Dental  Cosmos.     Vol.  XXX Y.) 

M.  MoRGENSTERN.  Yorliiufige  Mittlieilung  iiber  das  Yorkommen  von  Nerven 
in  den  harten  Zabnsubstanzen.     [Dent   Monatssch.  f.  ZahnJieilk      1892.) 

0  Walkhoff.  Neue  Untersucbungen  iiber  die  Path ohistologie  des  Zahnbeins. 
[Deut   Monatssch.  f  Zahn.hcilk.      189:i.) 

F.  Abbott.     Congenital  Defects  in  Enamel      [Dental  Cosmos.     1891.) 

J.  W.  DuxKERLEY.  The  Development,  Eoi-ms,  Structure,  and  Modes  of  At- 
tachment of  Teeth,  Human  and  Comparative  [British  Journal  of  Dental  Science. 
1890  ) 

C.  S.  Tomes  Studies  on  the  Growth  of  the  Jaws.  (Trans.  Odont.  Soc!  Gr. 
Britain.     1891  ) 

A.  Hopewell.  On  a  New  Method  of  Preparing  Sections  of  Teeth  and  Bone, 
to  Demonstrate  the  Hard  and  Soft  Tissues  in  Combination.  (Trans.  Odont.  Soc. 
Gr.  Britain.      1891  ) 

W.  R.  Garrould.  Some  Observations  on  the  Development,  Diseases,  and 
Deformities  of  the  Upper  Jaw.     [British  Journal  of  Dental  Science.     1891.) 

J.  I.  Hart.    3Iinute  Structure  of  Dentine.     [Dental  Cosmos.    Yol.  XXXIII  ) 

W.  C.  Barrett  The  Condition  of  the  Dentine  in  Pulpless  Teeth.  [Dental 
Cosmos.     Yol.  XXXIY  ) 

G.  H.  McCausey.     Enamel,  Dentine,  and  Xerve.     [Dental  Revieiv.     1892.) 
G    H.  McCausey.     Development  of  the  Teeth.     [Dental  Review.     1891.) 

J  Hltmphreys.  The  Development  of  Human  Teeth.  [Monthly  Reriew  of 
Dental  Surgery.     1892.) 

A  H.  Smith.  Same  Points  on  the  Patho-Histology  of  the  Dental  Pulp. 
[Monthly  Review  of  Dental  Surgery.     1892.) 

C.  Heitzmann  and  F.  A.  Roy.  Contributions  to  the  Minute  Anatomy  of 
the  Cementum      [Intern.  Dent.  Jour.     1892.) 

R  R  Andrews.  A  Contribution  to  the  Study  of  the  Development  of  the 
Enamel.     [Intern.  Dent.  Jour.     1893.) 

A.  H.  Smith  Some  Observations  on  the  Cellular  Elements  of  the  Dental 
Pulp.     [British  Journal  of  Dental  Science      1893.) 

A.  T.  BRUN■^'.  Beitrage  zur  Kenntniss  der  Zahnentwicklung.  [Arch.  f.  Micro. 
Anat      1891.) 

—  Ballowitz.  Das  Schmelzorgan  der  Edentaten,  etc.  [Arch,  f  Micro.  Anat. 
1892.) 

C.  Rose      Beitrage  zur  Entwicklung  der  Edentaten.     [Anat.  Anzeiger.    1892.) 

P.  Ereukd  Beitrage  zur  Entwicklungsgechichte  der  Zahnanlagen  bei  Xage- 
thieren.     [Arch  f.  Micro.  Anat      1892  ) 

R.  Mahn.  Bau  und  Entwicklung  der  Molaren  by  Mus  und  Arvicola.  Er- 
langen,  1891.) 

E.  ZucKERKAXDL  tjber  das  epitheliale  Rudiment  eines  4"="  Mahlzahns  beim 
Menschen.     [Akacl  d.  Wissensch.     Wien,  1892.) 

G.  RuDAS.  Uber  mangelhafte  Entwicklung  der  Zahne  und  der  Zahngewebe. 
[Odontoskop.     1893.) 


628  LITERATURE. 

G.  El'DAS.  tJber  eine  auf  der  Zahnwurzel  seltener  beobachteten  Yeranderung 
{Odonioskop.     1893.) 

G.  EuDAS.     Yon  den  Interglobular-Raumen.     [Odontoshyp.     1893.) 

G.  Eetzius.     i^Deut.  Monatssc.hr.  f.  ZahnheUk.     1893.     P.  59.) 

H.  BuRCHARD.  Amelification  and  Epithelial  Development.  [Denial  Cos- 
mos.    Vol.  XXX YI.) 

W.  E.  Christexsen.  Dr  Weil's  Method  of  Preparing  Teeth  for  Microscopical 
Stud3^     {Denial  Cosmos.     Yol.  XXX YI.) 

J.  ScHAFFER.    tiberRoux'sche  Kaniileinmensehlichen  Zahnen     Leipzig,  1890 

C  ROsE.  Tiber  die  Nervenendigungen  in  den  Zahnen.  (Deut.  Monaisschr.  f. 
ZahnheUk.     1898.) 

W.  Lepkowski.  Beitrag  zur  Histologic  des  Dentins  niit  Angabe  einer  neuen 
Methode      [Anat  Anzeiger.     1892  ) 

J.  H.  Mttmmery      Einige  Punkte  liber  Structur  und  Entwickkmg  des  Dentins.  ' 
(Philos.  Trans   of  the  Royal  Society  of  London.     1898  ) 

E.  Magitot.  Contribution  a  Thistoire  des  mutilations  dentaires.  [Revue  et 
Arch.  Suisses  d'Odontologie.     Dec,  1890.) 

O.  Walkhoff.  tJber  die  Bedeutung  des  Yitalen  Princips  im  Zahnbein 
{Deut.  Monaisschr.  f.  ZahnheUk.     1893.) 

G.  Carpenter  and  R.  D.  Pedley.  Primary  Dentine  in  its  Relation  to  Rickets 
[Lancet     1892.) 

CHAPTER    XYI. 

J.  HuTCHixsox.  On  the  Influence  of  Hereditary  Syphilis  on  the  Teeth 
(Trans.  Odont.  Soc.  Gr.  Britain.     1850  and  1860.) 

B.  W.  Richardson.  Medical  History  and  Treatment  of  Diseases  of  the  Teeth, 
etc      London,  1860. 

L.  Dowx.     (Trans.  Odont.  Soc.  Gr.  Britain.     1871  ) 

E.  Magitot.     Traite  de  la  Carie  Dentaire      Paris,  1867. 

H.W.Williams.     Recent  Advances  in  Ophthalmic  Science.     Boston,  1881. 

B.  Hell.  Effects  of  Syphilis  on  the  Teeth  and  Mouth.  [Monthly  Review  of 
Dental  Surgery.     London,  1872.) 

T.B.Hitchcock.     Syphilitic  Teeth.     [Johnston  s  Denial  Miscellany      1874.) 

C.  T.  Cr.SHMAN.  A  Curious  Case  of  Anomalous  and  Xon-development  of 
Teeth.     [A7n   Jour,  of  Dent.  Sci      1855.) 

C.  T.  CfSHMAN.  Entire  Absence  of  all  the  Teeth.  [Am.  Jour,  of  Dent.  Sci. 
1855  ) 

J.  L.  Levison.     On  Dental  Deformities.     [Am   Jour,  of  Dent.  Sci.     1856.) 
Dr.  CoLBLTRx.    Anomalous  Development,  etc.     [A}n.  Jour,  of  Dent.  Sci.    1856.) 
S.  WiLKS.     Hereditary  Syphilis'     [Dental  Cosmos.     Yol.  YIII.) 
S.  WiLKs.     Malfomied   Tooth    from    Hereditarv   Svphilis.       [Dental    Cosmos. 

Vol.  VIII.     P.  280.) 

G.  H.  Perixe.     Congenital  Atrophy  of  Temporary  Teeth.     [Missouri  Dent 

Jour.     1876.) 

J.W.White.     Syphilitic  Teeth.     [Br  Uish  Journal  of  Dental  Science.     1884.) 
J.  Hutchixsox.     a  Surgeon  on  Certain  Diseases  and  Malformations  of  the 

Teeth.     (Trans   Odont  Soc   Gr.  Britain.     1888.) 

H.  Moox.      On   Irregular   and   Defective   Tooth    Development.      [Johnston's 

Dental  Miscellany      1877.) 

D.  B  Eeeemax.  The  Effect  of  Eruptive  Diseases  on  the  Teeth.  [Denial 
Review.     1890.) 


LITERATURE.  629 

J.  S.  Dodge,  Jr.  Anomalous  Affections  of  the  Teeth.  [A»i  Jonr.  of  Dent. 
Sci.     1859  ) 

0.  y.  ZsiGMOXDY.  On  Congenital  Defects  of  the  Enamel.  [Ldern.  Doit. 
Jour.     1893.) 

M.  Xapier.  ^lanifestations  of  Syphilis  in  the  Teeth.  [Denial  Cosmos.  Vols 
XYIII.  and  XIX.) 

—  Cartwrioht.     Syphilitic  Teeth.     [Dental  Cosmos.     Vol    XYIII.) 

—  QuiNET.     On  Syphilitic  Teeth.     [Dental  Cosmos.     Yol.  XXII.) 

F.  Abbott.  Studies  of  the  Pathology  of  Enamel  of  Human  Teeth,  etc 
[Dental  Cosmos.     Yol.  XXYII  ) 

E.   L.   Keyes.     The  Hutchinson  Teeth.     [Dental  Cosmos.     Yol.  XXYII.) 

A.  H.  Thompson.  Pathological  Heredity  and  Gouty  Teeth.  [Dental  Cosmos. 
Yol.  XXYIII.) 

J.  Hutchinson.     Syphilitic  Teeth.     [Dental  Cosmos.     Yol.  XXXI.) 

0.  ZsiGMOXDY.  Congenital  Defects  of  the  Enamel.  [Dental  Cosmos.  Yol. 
XXX  Y.) 

A.  G.  Eriedrichs.     Syphilitic  Teeth.     (Trans.  Am  Dent  Ass.     1883.) 

H.  Moon.  On  Irregular  and  Defectiye  Tooth  Development.  (Trans.  Odont. 
Soc.  Gr.  Britain.     1876  ) 

O.  "Walkhoff.  Die  Defecte  der  harten  Zahnsubstanzen  ohne  Erweichung. 
[Deut.  Monatsschr.  f.  Zahnheilk.     1886.) 

J.  Scheff,  Jr.  tJber  Eudimentare  (Schmelzlose)  Ziihne  [Deut.  Monatsschr. 
f.  Zahnheilk.     1888.) 

Ed.  Albrecht.  Hereditiire  Syphilis  und  Abnorme  Zabnbildung.  [Deut. 
Vier.  Jahrseh.  f  Zahnheilk.     1862.) 

M.  Parrot.  La  Ehachitis  et  la  Syphilis  hereditairc.  (Trans.  Intern.  Med 
Congress      1881.) 

CHAPTEE    XYIII. 

E.  Magitot  Concerning  the  Syphilitic  Origin  of  Ehachitis.  [Archives  of 
Dentistry.     1885.) 

—  BoHN.     Ehachitis  and  Dentition.     [Dental  Cosmos.     Yol.  XI  ) 

C.  C.  EiTCHiE.  Pickets  a  Cause  of  Late  Dentition.  [Dental  Cosmos.  Yol. 
XIII.) 

—  Edes.     Ehachitic  Cat.     [Dental  Cosmos.     Yol.  XYII.) 

—  Seemaxn.  Pathogenesis  and  Etiology  of  Ehachitis.  [Dental  Cosmos.  Yol. 
XXIL) 

M.  Parrot.     Hereditary  Syphilis  as  the  Constant  Cause  of  Pickets.     [Dental 
Cosmos.     Yols   XXIII  and  XX  Y.) 
E.H.Bradford.     Causation  of  Ehachitis.     [Dental  Cosmos.     Yol.  XXIII.) 
J.  M.  Keating.     The  Ehachitic  Diathesis.     [Dental  Cosmos.     Yol.  XXY.) 
M.  Kassowitz.     Pathogenesis  of  Ehachitis      [Dental  Cosmos.    Yol.  XXYII.) 

.     Hereditary  Syphilis.     [Dental  Cosmos.     Yol.  XXYIL) 

.     Pickets  and  Syphilis      [Dental  Cosmos.     Yol   XXX.) 

—  BoTJCHrT.  De  la  Syphilis  comme  cause  de  Ehachitisme  et  de  Malformation 
dentaire.     (Trans   Intern.  Med   Congress.     London,  188  L.) 

CHAPTEE    XIX. 

W.  H.  Atkinson.     Dental  Pulps.     [Dental  Cosmos.     Yol.  X.) 
J.-  Brockway.     Dental  Pulp,  etc.     [Dental  Cosmos.     Yol.  X.) 


630  LITERATURE. 

L.  C.  Ingeesoll.  The  Eelations  of  the  Tooth-Pulp  to  the  other  Tooth-Tissues. 
[Dental  Cosmos.     Vol.  XXXI.) 

W.  X.  SirJDDUTH.     The  Dental  Pulp.     [Denial  Cosmos.     Vol.  XXXIII.) 

C.  F.  W.  BoDECKER.  The  Minute  Anatomy,  Physiology,  Pathology,  and 
Therapeutics  of  the  Dental  Pulp.     (Tr-ans.  jST.  Y.  Odont.  Soc.     1881.) 

J  H.  McCausey.  The  Relations  of  the  Tooth-Pulp  to  the  other  Tooth-Struc- 
tures.    (Tran.s    N.  Y.  Odont.  Soc.     1890.) 

F.  Y.  Clark.     Diseases  of  the  Dental  Pulp.    (Trans.  Am.  Dent.  A.ss.     1868.) 

CHAPTEPv    XX. 

C.  Wedl.     tJber  Gefassknjiuel  im  Zahnperiost.     {Vh-chov;'s  Archiv.     1881.) 

L.  C.  I^'GERSOLL.  The  Alveolar  Dental  Membrane,  etc  [Dental  Cosmos. 
Vol.  XXVII.) 

I.  P.  WiLSOX.  The  Apical  Portion  of  the  Cementum,  Physiologically  and 
Pathologically  Considered.     [Dental  Cosmos.     Vol.  XXX  ) 

—  HoHL  Die  Befestigung  des  Zahns  in  der  Alveole  [Deut.  Vier.  Jahrsch  f. 
ZaJmheilk.     1867  ) 

S  Bennett.  The  Adaptation  of  the  Teeth  to  the  Alveolar  Process.  [Monthly 
Review  of  Dental  Surgery.     1884.) 

F  Harrison.  Notes  on  the  Alveolar  Dental  Membrane.  [Monthly  Review 
of  Dental  Surgery.     1884.) 

CHAPTEPv    XXI. 

G.  W.  Ellis.     Dentition,  etc.     [Deiital  Cosmos.     Vols.  VIII,  IX,  X  ) 
J.  D   White.     First  Dentition.     [Dental  Cosmos.     Vol.  XXVII.) 

C.  iST  Peiece.  The  Deciduous  Teeth  :  Their  Eruption  and  Removal.  (Trans. 
Am.  Dent.  Ass.     1887.) 

R  Baume.  Der  Durchbruch  der  Zahne  [Deut.  Vier.  Jahrsch.  f.  Zahnheilk. 
1873.) 

M.  EiCHLEE  Dentition.  (In  Handb.  der  Zahnheilk.,  von  J.  Scheft",  Jr. 
Wlen,  1891.) 

0.  Fiedler,     tjber  die  Erste  Zahnung.     Halle,  1891. 

R   HoEENES.     Zur  Kenntniss  der  Milchbezahnung.     Wien,  1892. 

W.  H.  Flowee  Notes  on  the  First  or  Milk  Dentition  of  the  3Iammalia. 
(Trans.  Odont   Soc.  Gr.  Britain      1870.) 

CHAPTER    XXII. 

W.H.Elliot.     Absorption  of  Dental  Bone.     [Am.  Jour,  of  Dent.  Sci.     1847.) 
J.  H.  McQuiLLEN      Absorption   of  the  Roots   of  Deciduous   Teeth.     [Penn. 
Jour,  of  Dent.  Sci.     1874.) 

J.  H.  McQuillen.  Absorption  of  the  Fangs  of  Deciduous  Teeth.  [Dental 
Cosmos.     1860.) 

C.  N.  Peirce.  Calcification  and  Decalcification  of  the  Teeth.  [Dental  Cosmos. 
Vol.  XXVI.) 

W.  X.  SuDDUTH.     Resorption  of  Tissue.     [Dental  Cosmos.     Vol   XXVIII.) 
F.  Abbott.     Microscopical  Studies  upon  the  Absorption  of  the  Roots  of  Tempo- 
rary Teeth.     [Dental  Cosmos.) 

F.  Abbott.     Report  on  Physiology.     (Trans.  Am.  Dent.  Ass.     1867.) 
J.  H.  McQriLLEN.     Absorption  of  the  Roots  of  the  Deciduous  Teeth.     (Trans. 
Am.  Dent.  Ass.     1875.) 


LITERATURE.  631 

E.  ScHWAETZKOPF.  Eesorption  der  Ztihnwurzeln  bei  Eegulirungen.  [Dent. 
Monatsschr.f.  Zahnheilk.     1887.) 

J.  Parkeidt.  Vollstandige  Eesorption  des  Zahnbeins  eines  Milclizalins 
[Deut.  Monatsschr.f.  Zahnheilk.    1890.) 

J.  V.  Mettnitz.     Das  Schwinden  der  Milchzalinwurzeln.     Wien,  1889. 

H.  J.  L.  Struikex.  Die  Eesorption  der  Milchzahne  imd  die  Odontokla-sten. 
{Centralbl.  f.  d.  Med.  Wiss.     1890.) 

G.  H.  Harding.  On  the  Proees.s  of  Absorption  in  Bone  and  Tooth-Structure 
(Trans.  Odont.  Soc.  Gr.  Britain.      1877.) 

W.  K.  Bridgemax.  On  the  Absorption  of  Bone  and  Dentine.  (Trans.  Odont 
Soc.  Gr.  Britain      1861.) 

CHAPTEE    XXIV. 

J.  M.  Keetil.  The  Physiology  and  Treatment  of  Sensitive  Dentine.  [Brit- 
ish Journal  of  Dental  Science.     1890.) 

T.  Gaddes.     Xotes  on  the  Anatomy,   etc  ,   in  Eelation   to  Dental  Diseases. 

[Dental  Review.     1891  ) 
A.  Harris.      Characteristics  of  the  Teeth,   etc.      [Am.   Jour,  of  Dent.  Sci. 

1841.) 

C.  N.  Peirce.     Dental  Diagnosis.     [Intern   Dent.  Jour.     1893.) 

H.  S.  Chase      History  of  Dental  Calculi.     [Mi.^isouri  Dent  Jour.     1869.) 

E.  C.  Chase      Tlie  Causes  of  the  Deposition  of  Salivary  Calculus.     [Missouri 

Dent  Jour.     187-2.) 

H.  JuDD.     Of  Dental  Tartar,  etc      [Missouri  Dent.  Jour.     1874.) 

L.  C.  IsTGERSOLL.     Diagnosis.     [Missouri  Dent.  Jour.     1878) 

G.  B.  Clemext.     Dental  Pathology.     (Archives  of  Dentistry.     1886) 

A.  Forget.     Dental  Anomalies,  etc      [Dental  Cosmos      Yol.  I.) 

A.     EoBERTSOX.     EHects  of  Disease  on  Teeth      [Dental  Comnos.     Vol.  I  ) 

T.    Laycock.      On  Physiognomical  Diagnosis  of    Disease.     [Dental   Cosmos. 

Vol.  III.) 

W.  H.  Atkixsox.     Temperament      [Dental  Cosmos      Vol   VI.) 

—  Hodges.     Salivary  Calculi.     [Dental  Cosmos.     Vol.  VII  ) 

H.  S.  Chase      Tartar:  Its  Conservative  Eifects     {Dental  Cosmos     Vol.  VII.) 

J.  McManits      Diagnosis      [Dental  Cosmos.     Vol   VII.) 

G.  J.  ZiEGLER.     Temperaments,  etc      [Dental  Cosmos.     Vol.  VIII.) 

G.  J.   ZiEGLEE      Influence  of  Extreme  Cold,  etc      [Dental  Cosmos.    Vol.  IX.) 

.     Illuminating  the  Interior  of  the  Living  Body.     [Dental  Cosmos. 

Vol.  IX.) 

G.  J.  ZiEGLER.     On  Heat  in  its  Vital  Eelations.     [Dental  Cosmos.    Vol.  IX.) 
M.  Bazix.      Differential  Diagnosis  between  Syphilis  and  Scrofula.     [Dental 

CosTnos.     Vol   XII.) 
J.  L.  Williams.     The  Influence  of  the  jS'ervous  System  on  the  Health  of  the 

Teeth  and  Mouth.     [Dental  Cosmos    -Vol.  XIV.) 

J.  E.  Gakretsox.     Diagnosis  in  Neuralgia      [Dental  Cosmos.     Vol.  XV.) 

A    D.  "Williams.     Care  in  Diagno.sis.     [Dental  Cosmos.     Vol.  XVI.) 

J.  C.  Scott.     Diagnosis.     [Dental  Cosynos.     Vol.  XVI. ) 

A.  Miller.     Neuralgia  Caused  by  Granules  of  Osteo-Dentine.     [Dental  Cosjnos. 

Vol   XVI.) 

L.  G.  Noel.     Eheumatic   Markings    upon  the  Teeth.     [Dental  Cosmos.     Vol. 

XVII.) 

E.  D.  S.  NiLES.     Odontolithns,  etc.     [Dental  Cosmos.     Vol.  XXIII.) 


632  LITERATURE. 

L.  Elsberg.  Electric  Illumination  and  Cautery  of  the  Mouth.  {Dental  Cos- 
?nos.     Vol.  XXI Y.) 

E.  Magitot.  Ditferential  Diagnosis  of  Tic  Douloureux  and  Dental  Xeuralgia. 
(^Dental  Cosmos.     Yol.  XX YI  ) 

C.  J.  EssiG.     Differential  Diagnosis.     {Deiiial  Cosmos.     Yol.  XX YI.) 

W.  C.  Phillips.  Transillumination  of  the  Antrum,  etc.  {Dental  Cosmxjs. 
Yol.  XXXIII.) 

W.  H.  Metcalf.     Dental  Diagnosis      {Dental  Cosmos.     Yol.  XXX Y.) 

O.  WiTZEL.  Die  Affectionen  des  Mundes  hei  Diahetes  mellitus.  {Deut.  Vier. 
Jahrsch.  f.  Zahnheilk.     1879  ) 

G.  NiEMETER.    Unsichere  Diagnosen.    {Deut.  Vier.  Jahrsch.  f.  ZaJinheilk.   1882.) 

J.  Parreidt.  Zur  Diagnose  der  Pulpareizung  und  des  empfindlichen  Zahn- 
beins      {Deut.  Monatsschr  f.  Zahnheilk.     1883  ) 

R.  P.  H.  King.  Some  Points  in  Dental  Diagnosis.  {British  Journal  of  Dental 
Science.     1885.) 

L.  Elsberg.     ^Trans   Xew  York  Odont.  See.     1881.) 

W.  Pretxdexthal.  Die  Diux-hleuchtung  in  der  Laryngologie.  {Med.  Wo- 
chenschr.     1889.) 

T.  HERTSfG.  Die  Electrische  Diu-chleuchtung  der  Highmorshohle  hei  Empvem. 
{Berliner  Klin.  Wochensehr.     1887.) 

—  ZiEM.  Durchleuchtung  der  Oherkieferhohle.  {Berliner  Klin.  Wochensehr. 
1890.) 

—  YoHSEX.  Zur  Electrischen  Beleuchtung  und  Durchleuchtung  der  Ivorper- 
hohlen.     {Berliner  Klin.  Wochensehr.     1890.) 

—  Srebrst.  Zur  Frage  der  Durchleuchtung  der  Oherkieferhohle  hei  Empyem 
derselben.     {Berliner  Klin    Wochensehr.     1890.) 

W.  D.  Miller.  The  Deposits  upon  the  Teeth,  with  Special  Eeference  to  Green 
and  Metallic  Deposits      {Denial  Cosmos      1894.) 

M.  Basttr.  Die  Zahnhelage  (In  Handh.  der  Zahnheilk.,  von  J.  Scheff,  Jr. 
Wien,  1892.) 

Pv.  OTTOLEXGri.  {Dental  Cosmos  Yol.  XXXIY.  P.  707.)  (Trans.  Dent. 
Soc.  State  of  Xew  York      1893  and  1894  ) 

T.  Heryxg.  The  Electric  Light  in  Empyema  of  the  Antrum.  {British  Journal 
of  Dental  Science.     1889.) 

.1.  Maughajn-.  Remote  Pain  in  Dental  Disease.  (Trans.  Odont.  Soc.  Gr. 
Britain.     1893.) 

CHAPTERS    XXY-XXYII. 

J.  31.  Howe.     Secondary  Dentine      (Trans.  X.  Y.  Odont.  Soc.     1877.) 

G.  Bltjme.     tjher  die   fortwahrende  Yerknocherung   ini  Zahnkanale.     {Der 

Zahnarzt.      1851  ) 

W.  DiECK.     Dentin   Xeuhildungen  von    Seiten   der   durch    eine  Zahnfractur 

freigelegten  Pulpa,  etc.     {Verh.  d.  Deut    Odont   Ge.sell.     Bd.  II.) 

R.  HoHL.    ther  die  Entwicklung  der  inneren  Odontome.    {Deut  Tier.  Jahrsch. 

f.  Zahnheilk.     1872.) 

R.  Baume.     Bemerkungen  iiber  interstitielle  Dentikel.     {Deut.  Vier.  Jahrschr. 

f.  Zahnheilk.     1874.) 

G   Hexry.     Remarks  on  "Inostosis."    (Trans.  Odont.  Soc  Gr.  Britain.    1871) 

J.  F.  Flagg.     Tubular  Condensation.     {Dental  News  Letter.     1857.) 

J.  H.  McQtjillex.     Caries  Arrested  by  Consolidation  of  the  Dentinal  Tubules 

{Dental  jVeius  Letter.     1859.) 


LITERATURE.  633 

A.  F.  To^vxsEXD.     Abrasion  of  the  Teeth.     {Dfntal  Cosmos.     Vol.  XXXII.) 

J.  Taft.     Abrasion  of  the  Teeth.     {Am.  Jour,  of  Dent.  Sci.     1847.) 

R.   E.  Andrews.     {Intern.  Dent.  Jour.    1889.    P.  169.    (Reaction  of  Fillings.) 


CHAPTER    XXVIII. 

C.  H.  RoBixsox.     Abrasion  and  Erosion.     {Dental  Review.     1889.) 

R.  Brooks.     Ero.sion  of  the  Enamel.     {Dental  Neios  Letter.     1852.) 

J.  D.  W.     Tooth  Edge.     {Denial  News  Letter.     1857.) 

J.  M.  Howe.  A  Contribution  to  the  Study  of  Erosion.  {Litem.  Dent.  Jour. 
1893.) 

L.  A.  Obriax.     Erosion.     {Dental  Cosmos.     Vol.  XXX.) 

I.  B.  Datexport.  Etiology  of  Chemical  Abrasion,  etc.  (Trans.  Am.  Dent. 
Ass.     1881.) 

.1.  C.  TiLGE.  IJber  die  Atrophic  und  Erosi^m  der  Zahne.  {Der  Zahnarzt. 
1846.) 

—  Reid.     i'ber  die  Erosion  der  Zahne.     {Der  Zahnarzt.     1848.) 

—  Albrecht.  Atrophie  und  Erosion  der  Zahne  und  Folgen  von  Ernahrungs 
storungen  zur  Zeit  der  Zahnbildung.     {Der  Zahnarzt.     1861.) 

L.  H.  Hollander.  tJber  Erosion  der  Ziihne.  ( Verh.  d.  Deut.  Odont.  Gesell. 
Bd.  I.) 

0.  ZsiGMONDY.  Uber  die  Enstehung  der  Keilformigen  Einschnitte  an  der 
Facialseite  der  Zahnhiilse,  etc.     {Deut.  Vier.  Jahrsch.  f.  Zahnheilk.     1873.) 

R.  B  aume.  Die  Keilformigen  Defects  an  den  Zahnhalsen,  Zerstorung  der  Zahn- 
substanzen  durch  Alkali  en.     {Deut.  Vier.  Jahrsch.  f.  Zahnheilk.     1876.) 

—  Herrmax.     Abrasion  der  Zahne.     {Deut.  Vier.  Jahrsch.  f.  Zahnheilk.    1879.) 

—  Xiemeyer.  Die  Keilformigen  Defecte.  {Deut.Vier.  Jahrsch.  f.  Zahnheilk. 
1879.) 

G.  Y.  Black.     Abra.sion  and  Erosion  of  the  Teeth.      (American  System  of 

Dentistry.     Philadelphia,  1886.) 

F.  Btjsch.     tJber  die  Entstehung  der  Erosionen  an  den   Kronen  der  Ziihne. 

{Deut.  Med.  Wochenschr.     1886.) 

W.  K.  Bridgemax.     On  the  Electro-Chemical  Action  of  Metallic  Substances 

upon  the  Teeth.     (Trans.  Odont.  Soc.  Gr.  Britain.     1869.) 
E.  C.  Kirk.     Erosion.     {Intern.  Dent.  Jour.     1886.) 
C.  R.  E.  Koch.     Abrasion  and  Erosion.     {Dzntal  Cosmos.     Vol.  XV.) 
C.  A.  KixGSBTTRY.     Abrasion  of  the  Teeth.     {Dental  Cosmos.     Vol.  XX.) 
C.  E.  Kells.     Erosion.     {Dental  Cosmos.     Vol.  XXXIII.) 
E.  T.  Darbt.     Dental    Erosion   and   the   Gouty    Diathesis.     {Dental    Cosmos. 

Vol.  XXXIV.) 

H.  .luDD.     Spontaneous  or  Chemical  Abrasion.     {Missouri  Dent.  Jour.     1873.) 
M.  Basttr.  Die  Erworbenen  Defecte  der  harten  Zahnsubstanz.     (In  Hondb. 

der  Zahnheilk.,  von  .1.  Scheff,  Jr.     Wien,  1891.) 

A.  S.  Underwood.     On  Erosion  in  Connection  with  Some  Points  in  the  Minute 

Anatomy  of  Enamel.     (Trans.  Odont.  Soc.  Gr.  Britain.      1888.) 

S.  J.  Hutchinson.     A  Note  on  Erosion.     (Trans.   Odont.  Soc.  Gr.  Britain. 

1888.) 

A.   Coleman.      Erosion  of  the  Teeth.      {Monthly  Review  of  Dental  Surgery. 

1881.) 

S.  G.  Perry.     Erosion  of  the  Teeth.     {Intern.  Dent.  Jour.     1893. ) 

42 


634  LITERATURE. 

C.  H.  KoBiiSrsoJT.     Abrasion  and  Erosion.     {Denial  Review.     Vol.  III.) 
G.  J.  Friedrichs.     Erosion  of  the  Teeth.     [Dental  Cosmos.     Vol.  XXI.) 
L.  A.  Obrian.     Erosion.     [Dental  Cos^nos.     Vol.  XXX.) 

W.  H.  Trueman.     Erosion.     [Intei^n.  Dent.  Jour.     1891.) 

CHAPTEK    XXX. 

Dr.  Perry,     Exostosis.     [Dental  Neivs  Letter.     1853.) 
S.  M.  Shepherd.     Alveolar  Exostosis.     [Ain.  Jour,  of  Dent.  Sci.     1841.) 
J.  KoBiNSON.     Dental  Exostosis.     [Am.  Jour,  of  Dent.  Sci.     1846  ) 
M.  Koxjx.     On  Exostosis.     [A^n.  Jour,  of  Dent.  Sci.     1848.) 

D.  Vandenbxjrgh.  Observations  on  Exostosis.  [A7n.  Jour,  of  Dent.  Sci. 
1850.) 

W.  C  Barrett.     Exostosis  or  Dental  Osteoma.     [Indep.  Pract.     1886.) 
H.  S.  Chase.     Exostosis.     [Missouri  Dent.  Jour.     1875.) 

E.  L.  WiLLARD.  Exostosis  of  the  Pang  of  a  Tooth,  with  Osteo-Sarcoma  of  the 
Maxillary  Bone.     [Dental  Cosmos.     Vol.  VIII.) 

J.  H.  McQuiLLEN.  Case  of  Cemental  Hypertroph}-,  [Dental  Cosmos.  Vol. 
XIII.) 

F.  Abbott.    Hyperostosis  of  Eoots  of  Teeth.    [Dental  Cosmos.   Vol.  XXVIII.) 
J.  E.  Cravens.     Dental  Exostosis.     (Trans.  N.  Y.  Odont.  Soc.     1881.) 

Gr.  Welland.  Einige  Worte  liber  die  Exostosen  der  Zahne.  [Der  Zahnarzt. 
1846.) 

G.  A.  Oenicke.     Tiber  Hypertrophia  dentium.     [Der  Zahnarzt.     1848.) 

W.  Keichel.  tjber  Gesichts-  und  Kopfschmerzen  als  Polge  von  krankhaft 
verandei'ten  Zahnwurzeln,  hauptzachlich  von  Exostosen  derselben.  [Der  Zahn- 
arzt.    1852.) 

E.  Kroenele.     tJber  eine  Exostose,  etc.     [Der  Zahnarzt.     1854.) 

L.  A.  Weil.  tJber  Cementhyperplasie.  [Oest.  Ung.  Vier.  Jahrschr.  f. 
Zahnheilk.     1891.) 

D.  Headridge.  a  Case  of  Diftuse  Osteoma  of  the  Lower  Jaw.  [British 
Journal  of  Dental  Science.     1893.) 

D.  E.  Catjsh.     Exostosis.     (Trans.  Odont.  Soc.  Gr.  Britain.     1890.) 

CHAPTER    XXXI. 

C.  PvOKiTANSKY.     Handb.  d.  Allg.  Pathol.  Anat.     1846. 

C.  EoKiTANSKY.  tJber  das  Auswachsen  der  Bindegewebssubstanzen  und  die 
Beziehnng  dei-selben  zur  Entziindung.  [Sitzungsher.  der  Wiener  Akad.  der  Wiss. 
1854.) 

R.  ViRCHOW.  iTber  Parenchymatose  Entziindung.  [Vij^chow's  Arch.  Bd. 
IV.     1862.) 

R.  ViRCHOW.  tJber  die  Theilung  dor  Zellenkerne.  ( Virchow's  Arch.  Bd. 
XI.) 

J.  Cohnheim.  tJber  das  Verhalten  der  fixen  Bindegewebskorperelicn  bei  der 
Entziindung.     [Virchoiv's  Arch.     Bd.  XIV.) 

—  Waller.     [Philosoph.  Magazine.     1846.) 

S.  Stricker.  Studien  liber  den  Bau  und  das  Leben  der  Capill.  Blutgefasse- 
[Sitzungsher.  d.  Wiener  Akad.  der  Wiss.     1865.) 

J.  Cohnheim.  tJber  die  Entziindung  und  Eiterung.  [Virchow's  Arch. 
Bd.  XL) 


LITERATURE.  635 

S.  Stricker.  Studien  aus  dem  Institute  f.  Experimentelle  Pathologie  in 
Wien,  1870. 

Also  a  series  of  articles  by  Stricker  and  some  of  his  pupils  in  the  Wiener  Med. 
Jahrb.,  1871-1881. 

C.  Heitzmann.  Studien  am  Kuochen  und  Knorpel.  ( Wioier  Med.  Jahrb. 
1872.) 

C.  Heitzmanx.  tjber  die  Riick-  und  ]S'eul)ildung  von  Blutgefassen  in  Knochen 
und  Knorpel.     (  Wie^ier  Med.  Jahrb.     1873.) 

C.  Heitzmais^n.  Die  Entziindung  der  Beinhaut  des  Knochens  und  des  Knor- 
pels.     [Sitzungsher.  d.  Wiener  Akad.  der  Wlss.    1873.) 

—  EedferjST.    Abnormal  Nutrition  in  the  Articular  Cartilages.    London,  1850. 

—  RxjSTiZKY.  Untersuchungen  iiber  Knocheneiterung.  (  Wiener  Med.  Jahrb. 
1871.) 

E.  YoLKMANX.     (Langenbeck's  ^7-c/i,./. /iKn.  Chirurgie.     1863.) 

H    LotsiSEX.     ( Virchovrs  Archiv.     Bd.  IV.) 

J.  HoEMOKL.     ilber  Callusbildung.     [Wiener  Med.  Jahrb.     1874.) 

P.  Graavitz  und  W.  DE  Bary.     {li\  Virchow's  Arch.     1887.) 

P.  Grawitz.     [Virchow' s  Arch.     1887.) 
■  C.  Weigert.     {Deid.  Med.  Wochenschr.     1892.) 

G.  Klemperer.  tJber  die  Beziehungen  der  Micro-Organismen  zur  Eiterung. 
{Zeitschr.f.  Klin.  Med.     1885.) 

A.  ZucKERMAXN.  tJber  die  Ursache  der  Eiterung.  [Ceniralb.  f.  Bacteriologie 
und  Paraskd.     1887.) 

R.  Koch      Aetiologie  der  Wundinfectionskrankh.     Leipzig,  1878. 

P.  Grawitz.  Beitrag  zur  Therapie  der  Eiterung.  ( Virchoiv's  Arch.  Bd. 
CXYI.) 

Kreibohm  vmd  Rosenbach.  Experimentelle  Beitrage  zur  Frage :  Kann 
Eiterung  ohne  Mitbetheiligung,  etc.     [Arch.  f.  Klin.  Chirurgie.     1888.) 

—  Brieger.     tJber  Ptomaine.     1885  und  1886. 

—  Schetjrlex.  Weitere  Untersuchungen  iiber  die  Enstehung  der  Eiterung,  ihr 
Terhiiltniss  zu  den  Ptomainen  und  zur  Blutgerinnung.  [Fortschritte  der  Med. 
1887.) 

D.  BiONDi.  Contributione  airetiologia  della  suppurazione.  [La  Riforma 
Med.     1886.) 

—  Kathan.     (In  Arch.f.  Klin.  Chirurgie.     Bd.  XXXVII.) 

L.    Heitzmann.      tJber  Eiterbildung  in   der  Lederhuut.      [Arch.  /.   Derma- 

tologie.     1892.) 

P.  J.  Kester.     Pus.     [Dental  Review.      1890.) 

G.  H.  McCatjsey.     Inflammation.     [Denial  Review.     1888.) 

G.  V.  Black.     Are  Micro-Organisms  necessary  to  Pus-Formation  ?     [Dental 

Review.     1887.) 

G.  V.  Black.     Recent  Theories  of   the  Formation  of   Pus.     [Indep.    Pract. 

1887.) 

W.  H.  Atkixsok.     Inflammation.     [Missouri  Dent.  Jour.     1878.) 

—  L^SOKOFF.  Suppuration  without  3Iicro-Organisms.  [Missouri  Dent.  Jour. 
1882.) 

G.  F.  Eames.     Intimate  Nature  of  Inflammation.     [Arch,  of  Dent.     1885.) 
J.  L.  SxTESSEROTT.     Inflammation.     [Dental  Cosmos.     Vol.  I.) 
W.  H.  Atkixsox'^.     Inflammation      [Dental  Cosmos.     Vols.  V  and  X.) 
G.  J.  ZiEGLER.     Periscope  of  Medical  and  General  Science  in  their  Relations 
to  Dentistry.     [Dental  Cosmos.     Vol.  VII.) 


636  LITERATURE. 

J.  F.  HiBBERT.     Pus-Formation.     (Dental  Cosmos.     Vol.  X.) 
W.  H.  Atkinson.     The  Origin  of  Pus.     [Dental  Cosmos.     Vol.  XXXI.) 
G.  S.  Dean.     Concerning  Suppurative  Inflammation.     [Dental  Cosmos.     Vol. 
XXXII.) 

D.  Pi.  Stubblefield.  Pus-Pormation  Pvevived.  [Dental  Cosmos.  Vol. 
XXXIV.) 

R.  B.  Winder.     The  Etiology  of  Pus-Formation.      [Dental   Cosmos.      Vol. 

XXXV.) 

L.  F.  Harvey.     Inflammation.     (Trans.  Dent.  Soc   State  of  N.  Y.     1876.) 
W.  H.  Atkinson.     Pus.     (Trans.  Dent.  Soc.  State  of  N.  Y.     1876.) 
W.  H.  Atkinson.     Inflammation.     (Trans.  Dent  Soc.  State  of  N.  Y.    1878.) 
G.  S.  WooDHEAD.     On    Inflammation    in    Bone.      (Trans.    Odont.    Soc.    Gr. 

Britain.     1893.) 

CHAPTEE    XXXII. 

L.   Ottoft.     Hypertrophy  of  the  Oral  Mucous  Membrane.     [Denial  .Revieiu. 

1892.) 

A.  C.  Hugenschmidt.     Lingual  Ulceration  of  an  Epitheliomatous  Appearance 

due  to  an  Upper  Full  Artificial  Denture.     [Dental  Review.     1892.) 

C.  A.  Harris.     Diseases  of  the  Gums.     [Am.  Jour,  of  Dent.  Sci.     1841.) 
H.    H.    Hayden.      The  Diseases  of   the   Gums.      [Am.   Jour,   of   Dent.  Sci. 

1841.) 

G.  Waite.     The  Gums,  etc.     [Am.  Jour,  of  Dent.  Sci.     1841.) 

L.  Koecker.     Extraordinary  Fungous  Disease  of  the  Gums,  etc.     [Am.  Jour. 

of  Dent.  Sci.     1843.) 

A.  A.  B.  Diseases  of  the  Mucous  Membrane,  etc.  [A)n.  Jour,  of  Dent.  Sci. 
1856.) 

Dr.  Goddard.     Hypertrophy  of  the  Gums.     [Dental  Register.     1856.) 

E.  B.  Eeynolds.    Mercurial  Stomatitis,  etc.    [Am.  Jour,  of  Dent.  Sci.    1856.) 
H.  S.  Chase.     Inflammation  of  the  Gums  and  Lips.     [Missouri  Dent.  Jour. 

1870.) 

Dr.  Williamson.     Aphthous  Disease  of  Dentition.     [Missouri  Dent.  Jour. 

1874.) 

H.  JrDD.     Gingivitis  in  Pregnant  Women.     [Missouri  Dent.  Jour.     1877.) 

.     Acute  Ulitis.     [Archives  of  Dentistry.     P.  95.     1885.) 

J.  G.  Templeton.     Calcic  Inflammation.     [Archives  of  Dentistry.     1889.) 
J.  P.  H.  Brovs^n.     Morbid  Growth  of  the  Gums.     [Dental  Cosmos.     Vol.1.) 

—  GooDE.     Cancrum  Oris.     [Dental  Cosmos.     Vol   VI.) 

—  Cochran.     Cancrum  Oris.     [Dental  Cosmos.     Vol.  IX.) 

T.  Waterman.     Hypertrophy  of  Gums      [Dental  Cosmos.     Vol.  XL) 
T.  R.  Glynn.     Cancrum  Oris.     [Dental  Cosmos.     VoL  XII.) 

—  Cripps.     Cancrum  Oris.     [Dental  Cosmos      Vol.  XXII.) 

—  Cleveland.     Cancrum  Oris.     [Dental  Cosmos.     Vol.  XXIII. ) 

J.  S.  Cohen.  Syphilitic  Inflammation  of  Gums.  [Dental  Cosmos.  Vol. 
XXV.) 

W.  Bryden.  Case  of  Cancrum  Oris  in  the  Adult.  [Dental  Cosmos.  Vol. 
XXV.) 

Prof.  Monti.     Aphthous  Stomatitis.     [Dental  Cosmos.     Vol.  XXVI.) 

Prof.  Monti.     Cancrum  Oris.     [De?ital  Cosmos.     Vol.  XXVI.) 

B.  M.  EiCKETTS.     Oidium  Albicans.     [Dental  Cosmos.     Vol.  XXIX.) 


LITERATURE.  637 

J.  D.  Patterson.  Diseases  of  the  Oral  Mucous  Membrane.  [Doital  Cosmos. 
Vol.  XXXIII.) 

E.  C.  KiNGSFORD.     Cancrum  Oris.     {Dental  Cosmos.     Vol.  XXXIV.) 

J.  W.  HiSEY.  A  Case  of  Extensive  Hypertrophy  of  the  G-ums.  {Dental  Cos- 
mos:    Vol.  XXXV.) 

J.  Lefotjlon.    tJher  die  Krankheiten  des  Zahnfleisches.    {Der  Zahnarzt.     1855.) 

C.  Krakau.    Stomatitis  Gangnenosa.     {Deut.  MoTiatsschr.  f.  Zahnheilk.    1885.) 
W.  D    Miller.      Ein  Beitrag  zur  Aetiologie  der  Leucoplakia  oris.      [Deut. 

Monutsschr.f.  Zahnheilk.     1892.) 

—  BoHX.  Die  Mundkrankheiten.  (Gerhard's  Handh.  der  Kinderkrankheiteii. 
Tiibingen,  1880.) 

G-.  ScHEFF.  Ei-krank.  d.  Mundschleimhaut.  (Handb.  der  Zahnheilk.  Wien, 
1892.) 

H.  Paschkls.  Syphilis  des  Mundes.  (Handb.  der  Zahnheilk.,  von  J.  Scheff, 
Jr.     Wien,  1892.) 

D.  M.  Sabater.    Some  Diseases  of  the  Gums,  etc.     {Intern.  Dent.  Jour.    1894.) 
J.  ArkOvy.      Gingivitis  nudata.     {Ocst.    Ung.   Vier.   Jahrschr.  f.   Zahiiheilk. 

1893.) 

—  V.  Kaczorowski.  Der  aetiologische  Zusammenhang  zwischen  Entziindung 
des  Zahnfleisches  und  anderweitigen  Erkrankungen.      {Deut.  Med.   Woch.     1885.) 

—  Galippe      Die  infectidse  arthro-dentare  Gingivitis.     1888. 

CHAPTEE    XXXIII. 

E.  TowxsEisrD.  Speculations  upon  Inflammation  of  Dentine,  etc.  {Dental 
News  Letter.     1853.) 

W.  D.  Miller.  Studies  on  the  Anatomy  and  Pathology  of  the  Tusks  of  the 
Elephant.     {Dental  Cosmos      1890-1891.) 

F.  BuscH.  Zur  vergleichenden  Pathologic  der  Zahne,  mit  besonderer  Beriick- 
sichtigung  des  Stosszahnes  des  Elephanten.  (Trans,  j^inth  International  Med. 
Congress.) 

C.  Heitzmann  and  C.  F.  W.  BOdecker.  Inflammation  of  Dentine 
(Eburnitis).     {Indep.  Pract.     1886.) 

C.  S.  Bate.     Abscess  in  the  Dentine.     (Trans.  Odont.  Soc.  Gr.  Britain.     1864.) 

CHAPTEPv    XXXIV. 

J.  ArkOvy.  On  the  Kelations  of  Pathological  Concretions  of  the  Tooth-Pulp 
to  Prosopalgia  (Tic  Douloureux).     (Monthly  Review  of  Dental  Surgery.      1882.) 

H.  Sewill.  The  Etiology  and  Pathology  of  Dental  Diseases,  etc.  {Monthly 
Review  of  Dental  Surgery.     1882.) 

—  Galen,  who  was  born  A.  D.  131.  Systemisches  Handb.  der  Zahnheilk.,  von 
Georg  von  Carabelli.     Wien,  1844. 

Georgii  Prochaska.  Operum  Minorum  Anat.  Physiol,  et  Path.  Argument!. 
Pars  II.     Viennte,  1800. 

—  Rousseau.  Anat.  Comp.  du  Syst.  Dent.  Chez  T Homme  et  Chez  les  Princip. 
Anim.     Paris,  1827. 

—  Raschkow.  Meletemata  Circa  Mammalium  Dentinum  Evolutionem. 
Warschau,   1835. 

A.  Hartung.     Verlarvte  Zahnkrankh.     Leipzig,  1824. 
J.  Bauer.     De  Odontalgia  Mon.     1830. 


638  LITERATURE. 

J.  G.  G.  Werth.     Die  Odontalgie.     Berlin,  1836. 

M.  MoRGEXSTEKN.  Einwanderung  von  Pilzen  in  die  harten  Zahnsubstanzen. 
{Deut.  MonatsscJir.  f.  ZaJmheilk.     1882.) 

J.  ArkOvy.  IJber  die  Bezieliungen  der  Pathologischen  Concretionen  der  Zahn- 
pulpa  zur  Prosopalgie.     [Jour.     1883.) 

L.  M.  Dennis.  Beobachtungen  iiber  ISTeuralgien,  welcbe  von  Zahnen  her- 
riihren,  ibre  Diagnose,  etc.     [Centralbl.  f.  Zahnhellk.     1884.) 

J.  ScHEFF,  Jr.  Zur  Diflferentialdiagnose  der  Pulpitis  gangraen.  total  humi., 
etc.     f^Oest.  Ung.  Vier.  Jahrsc}w\  f.  Zahnheilk.     1887.) 

A.  KoTHMAN.  Pathologic  und  Therapie  der  Pulpaki-ankbeiten.  (In  Handb. 
der  Zahnheilk  ,  von  J.  Scheff,  Jr.     Wien,  1891.) 

M.  ScHLENKER.  Pulpen  Odontinoide.  (Handb.  der  Zahnheilk.,  von  J.  Scheif, 
Jr.     Wien,  1891.) 

G.  KiRCHNER.  Aetiologie,  Diagnose  und  Therapie  der  Pulpakrankheiten  in 
nichtcariosen  Zahnen.     [Deut.  Monatssehr.  f.  Zahnheilk.     1892.) 

0.  Walkhoff.  Eine  Conservative  Behandlung  der  erkrankten  Zahnpulpa. 
Leipzig,  1888. 

C.  F.  W.  BOdecker.  The  Minute  Anat.,  Physiol.,  and  Therap.  of  the  Dental 
Pulp.     {Denial  Cosmos.     Vol.  XXI Y.) 

M.  LiPSCHNiTZ.  Uber  die  Atrophien  der  Pulpa  als  Folge  der  Bildung  von 
Ersatzdentin.     [Deut.  Monatssehr.  f.  Zahnheilk      1892.) 

R.  HoHL.     Uber  Neubilduugen  der  Zahnpulpa      Halle,  1868. 

E.  Albrecht.     Die  Krankheiten  der  Zahnpulpa.     Berlin,  1858. 

H.  Friedberg.  tjber  einige  Falle  von  Heilung  der  Prosopalgie,  etc.  (  Vir- 
chow's  Arch.     1860.     Bd.  18.) 

—  Underwood  and  Mills.  An  Investigation  into  the  Effects  of  Organisms 
upon  the  Teeth  and  Alveolar  Portions  of  the  Jaws.  (Trans  Intern.  Med.  Con- 
gress.    London,  1881.) 

1.  A.  Freeman.     Pulpitis      [Dental  Review.     1892.) 

H.  H.  Fitch.     Ossification  of  the  Pulp.     [Dental  Review.     1889.) 

F.  H.  Badger.     Ossification  of  the  Pulp      [Am.  Jour,  of  Dent.  Sci.     1853.) 
S.  J.  A.  Salter.     Intrinsic  Calcification  of  the  Permanent  Tooth-Pulp,  etc. 

[Am.  Jour,  of  Dent.  Sci.     1856.) 

E.  D.  Swain.     Calcific  Deposits  in  Tooth-Pulps.     [IndejJ.  Pract.     1886.) 
W.  P.  CooKE.     Formations  in  the  Pulp-Cavity.     [Litem.  Dent.  Jour.     1890.) 
E,.  Ottolengui.     Pulp-Stones  :   Their  Significance,  etc.     [Intern.  Dent.  Jour. 
1892.) 

A.  C.  Hugenschmidt.  Partial  Suppurating  Pulpitis,  etc.  [Jnter^n.  Dent. 
Jour.     1892.) 

E.  C.  Kirk.  Lime-Formations  in  the  Pulp-Chamber.  [Intern.  Dent.  Jour. 
1893.) 

H.  JuDD.     Ossification  of  the  Dental  Pulp.     [Missouri  Dent.  Jour.     1869.) 
H.  S.  Chase.     A  Calcified  Pulp.     [Missouri  Dent.  Jour.     1870.) 
H.  S.  Chase.     Calcification  of  the  Pulp.     [Missouri  Dent  Jour.     1876.) 
I.  Campbell.     Loss  of  Sight  by  Pulpitis.     [Missouri  Deni.  Jour.     1875.) 
W.  B.  Hayes.     Calcified  Pulp      [Missouri  Dent.  Jour.     1875.) 
T.  O.  Oliver.     Calcification  of  Pulp.     [Missouri  Dent.  Jour.     1875) 
A.  H.  Thompson.     Calcification  ISTodule.     [Missouri  Dent.  Jour.     1876.) 
H.  S.  Chase.     Pulp  Nodules.     [Missouri  Dejit.  Jour.     1876.) 
W.  H.  Atkinson.     Explosion  of  Teeth  with  Audible  Report.     [Dental  Cos- 
mos.    Vol.  II.) 


LITERATUEE.  639 

.     Explosion  of  a  Tooth.     {Deninl  Cosmos.     Vol.  VIII.     P.  588.) 

J.  H.   McQuiLLEX.     Calcification  of  the  Dental  Pulp.     [Dental  Cosmos.    Vol. 

X.) 
S.  p.  Cutler    Ossified  Pulps.     [Dental  Cosmos.     Vol.  XV.) 
A.  Coleman.  Spontaneous  Fracture  of  Teeth.    [Dental  Cosmos.    Vol.  XXV.) 
W.  D.  MiLLEE.     Gangrenous  Tooth-Pulps  as  Centers  of  Infection.     [Dental 

Cosmos.     Vol   XXX.) 
S    EoBicsEK.     Uber  die  wichtigsten  Consequenzen  der  in  Folge  von  Caries 

entblossten  Zahnpulpa,  etc      [Dent.  Vie?'.  JahrscK  f.  Zahnheilk.     1877.) 

L.  Hollander      Die    Odontalgie,    etc.      [Dent.   Vier.    Jahrsch.  f.   Zahnheilk. 

1876.) 

P.    Macaeoyici.     Pulpitis    Chronica    Idiopathica.      [Dental    Cosmos.      Vol. 

XXXV.) 

D.  E.  Caush.  Some  Changes  that  Take  Place  in  and  around  the  Pulp-Canal. 
[Dental  Cosmos.     Vol.  XXXV.) 

L.  C.  Ingersoll.  Relations  of  the  Dental  Pulp  to  the  Other  Tooth-Tissues- 
(Trans,  N".  T.  Odont.  Soc.     1878.) 

W.  DiECK.  Einige  Seltene  Beobachtungen,  Verkalkung  der  Pulpa,  welche 
durch  eine  Zahnfraktur  freigelegt  war,  etc.  (Verh.  d.  Deut  Odont.  Gesell., 
Bd.  IV.) 

—  Blusie.  Beitrag  zur  Pathologie  der  Dentinneubildungen  in  der  Pulpa. 
[Dent.  Vier.  Jahrsch.  f.  Zahnheilk.     1874.) 

—  Detznee.  Pulpa  Neubildung,  Pulpapolyp,  Hypertrophie  der  Pulpa, 
[Deut.  Vier.  Jahrsch.  f.  Zahiiheilk.     1875.) 

A.  ScHELLER.  Beitrag  zur  Symptomatologie  der  Pulpaerkrankungen.  [Deut. 
Vier.  Jahrsch.  f.  Zahnheilk.      1888.) 

J.  Parreidt.  Pulpitis  in  einem  nichtcariosen  Zahn.  [Deut.  Vier.  Jahrsch.  f. 
Zahnheilk.     1880.) 

A.  WiTZEL.  Die  Antiseptische  Behandlung  der  Pulpakrankheiten  des  Zahns. 
Berlin,  1879. 

A.  "WiTZEL.  Compendium  der  Pathologie  und  Therapie  der  Pulpakrank- 
heiten des  Zahns.     Hagen  i.  W.,  1886. 

A.  WiTZEL.     Deutsche  Zahnheilkd.  in  Vortragen.     Hagen  i.  W.,   1886. 

G.  V.  Black.  Pathology  of  the  Dental  Pulp.  Am  Sj^stem  of  Dentistry. 
Philadelphia,  1886. 

J.  Truman.     Diseases  of  the  Dental  Pulp.     Am.  System  of  Dentistry.     1886. 

M.  ScHLENKEE.  Untersuchungen  uber  die  Verknocherung  der  Zahnnerven, 
etc.     [Deut.  Monatsschr.  f.  Zahnheilk.     1888.) 

J.  E.  Gaeeetson.     Diagnosis  in  Neuralgia.     [Dental  Cosmos.  Vol.  XXV.) 

J.  A.  Klump.  The  Efi"ects  of  Malarial  Poisoning  on  the  Dental  Pulp.  [Dental 
Cosmos.     Vol.  XXV.) 

A.  KozMA.  Investigation  into  Statistics  of  Diseases  of  the  Tooth-Pulp,  Perios- 
teum, and  Alveolus.     [Mo7ithly  Review  of  Dental  Surgery.     1888.) 

E.  T.  Htjlme.  On  Calcifications  of  the  Dental  Pulp.  (Trans,  of  the  College 
of  Dentists  of  England      1861.) 

E.  Boll.     [Itx  Arch.  f.  Micr   Anat.     Vol.  IV.     Bonn,  1868.) 

F.  Ulei.ch.     (In  Zeitsch.  K.  K.  Gesell.  zu  Wien.     1852.) 

J.  Beuck,  Je.  Beitrage  zur  Histologic  und  Pathologie  der  Zahnpulpa.  Bres- 
lau,  1871. 

L.  A.  Weil.  Zur  Histologic  der  Zahnpulpa.     Leipzig,  1887. 

L.  A.  Weil.  Die  Odonthele  der  Zahnpulpa.     Bremen,  1890. 


640  LITERATURE. 

C.  E5sE.  Zur  Histolrtgie  dn-  Zahnpulpa.  [Deut.  Monaisschr.  f.  Zahnheilk. 
1892.) 

L.  A.  Weil.  Erwiderung  of  Dr.  C.  Eose's  Aufsatz,  "Zur  Lebre  der  Hist, 
der  Zahnpulpa.''     [Dad.  Monaisschr.  f.  Zahnheilk.     1892.) 

—  Partsch.  Die  von  Weil  beschriebene  Scbicbt  unter  den  Odontoblasten. 
[Deut.  Mo7iaisschr.  f.  Zahnheilk.     1892.) 

H.  BuRCHARD.  Ulceration  and  Abscess  of  the  Dental  Pulp.  [Dental  Cosmos. 
Yol.  XXXVI.) 

W.  D.  Miller.  An  Introduction  to  the  Study  of  the  Bacterio-Patbology  of 
the  Dental  Pulp.     [Dental  Cosmos.     Yol.  XXXYI. ) 

L.  Hattgast.  Ein  Fall  von  Pulpitis  chronica  idiopatbica.  [Oest.  Ung.  Vier. 
Jahrschr.f.  Zahnheilk.     1892.) 

S.  Cartwright.  On  Diseases  and  Treatment  of  the  Pulp.  (Trans.  Odont. 
See.  Gr.  Britain.     1861.) 

C.  S.  Tomes.  On  a  Case  of  Abscess  of  the  Pulp  in  a  Grampus.  (Trans.  Odont. 
See.  Gr.  Britain.     1872.) 

G.  W.  Watson".  Pathological  Conditions  of  the  Dental  Pulp.  (Trans.  Odont. 
Soc.  Gr.  Britain.     1892.) 

M.  Small.  Ossification  of  Pulp  in  Healthy  Tooth.  [Monthly  Review  of  Dental 
Surgery.      1880.) 

CHAPTER    XXXYIII. 

G.  D.  Pollock.     Alveolar  Abscess.     [Johnston's  Dental  Miscellany.     1876.) 
J.  M.  Biggs.     Suppurative  Intlammation  of  the  Gums  and  Absorption  of  the 
Gums,  etc.     [Johnston' s  Dental  Miscellany.     1878. ) 

0.  Coles.  Discussion  on  Biggs  s  Disease.  (Trans.  Odont.  Soc.  Gr.  Britain. 
1878.) 

M.  W.  Svtartz.  Pyorrho?a  Alveolaris  or  Eiggs's  Disease  of  the  Gums. 
[Dental  Revieio.     1892.) 

W.  P.  DiCKlKSOX.  The  Peridental  Membrane  and  Apical  Pericementitis. 
[Dental  Remew.     1891.) 

G.  Newkirk.  Some  of  the  Surgical  Aspects  of  Eiggs's  Disease,  etc.  [Dental 
Review.     1890.) 

A.  C.  HuGENSCHMiDT.  The  Occasional  Origin  of  True  Alveolar  Abscess  from 
Teeth  with  Living  Pulps.     [Dental  Review.     1890.) 

E.  .J.  Perry.  Diseases  of  the  Peridental  Membrane,  etc.  [Dental  Revieiv. 
1889.) 

W.  H.  Whitslar.  Tumors  of  the  Peridental  Membrane.  [Dental  Review. 
1889.) 

C.  T.  CxTSHMA^'.  Dental  Periostitis  and  Xecrosis,  etc.  [Dental  News  Letter. 
1851.) 

D.  B.  Whipple.     Periostitis.     [Dental  Xetvs  Letter.     1853.) 

J.  D.  White.     Absorption  of  Dentine.     [Dental  Neivs  Letter.     1853.) 

1.  I.  Greexwood      Alveolar  Abscess.     [Am.  Jour,  of  Dent.  Sci.     1842.) 

S.  P.  HuLLiHEN.     Abscess  of  the  Jaw,  etc.     [Am.  Jour,  of  Deni.  Sci.     1846.) 
S.  M.  Sheppard.     Spontaneous  Destruction  of  the  Alveoli.      [Am..  Jour,  of 
Dent.  Sci.     1847.) 

J.  C.  House.     Chronic  Absce.ss,  etc.     [Am.  Jour,  of  Dent.  Sci.     1859.) 
H.  N.  Wadsworth.     Alveolar  Abscess.     [Am.  Jour,  of  Dent.  Sci.     1859.) 
.     Alveolar  Abscess.     [Missouri  Dent.  Jour.     1869.) 


LITERATURE.  641 

H.  JxjDD.     Alveolar  Abscess.     [Missouri  Dent.  Jour.     1869.) 
C.S.Smith.     Alveolo-Dental  Periostitis.     [Missouri  Dejit.  Jour.     1869.) 
H.  JuDD.     Alveolar  Abscess.     (Missouri  Dent.  Jour.     1870.) 
W.  S.  Elliott.     Alveolar  Abscess.     [Missoicri  Dent.  Jour.     1870.) 
O.  Coles.     Dental  Periostitis.     {Missouri  Dent.  Jour.     1872.) 
T.  F.  RuMBOLD.     Destruction  of  tbe  Gums  and  Alveolar  Process,  etc.     [Mis- 
souri Dent.  Jour.     1873.) 

H.  S.  Chase.     Alveolar  Periostitis.     [Missouri  Dent.  Jour.     1873.) 

X.  E..  Htjrd.     Alveolar  Abscess.     [Missoicri  Dent.  Jour.     1874.) 

A.  W.  HARLA^".     Alveolar  Abscess      [Missouri  Dent.  Jour.     1875.) 

H.  S.  Chase.     Eesorption  of  Dental  Tissue.     [Missouri  Dent.  Jour.     1875.) 

P.  Masox.     Periostitis.     [Missouri  Dent.  Jour.     1875.) 

V.  PiETKiEWicz.    Alveolar  Dental  Periostitis.    [Missouri  Dent.  Jour.    1877.) 

W.  H.  Eames.     PyoiThoea  Alveolaris.     [Missouri  Dent.  Jour.     1878.) 

E.  T.  Darby.     Acute  and  Chronic  Alveolar  Abscess.     [Missouri  Dent.  Jour. 

1869.) 

M.  P.  PixLEY.     Alveolar  Abscess.     [Missouri  Dent.  Jour.     1880.) 

J.  S.  Smith.     Alveolar  Periodontitis.     [Missouri  Dent.  Jour.     1880.) 

C.  E.  E.  Koch.     Alveolar  Abscess.     [Missouri  Dent.  Jour.     1880.) 

L.  C.  IxGERSOLL.     Alveolar  Abscess.     [Missouri  Dent.  Jour.     1880.) 

L.  C.  Ij.'Geksoll.     .Uveolar  Ulceration  Distinguished  from  Alveolar  Abscess. 

[Missouri  Dent.  Jour.     1881.) 

G.  H.  Harbing.     On  the  Process  of  Absorption  in  Bone  and  Tooth-Structure. 

[Missouri  Dent.  Jour.     1 882. ) 

G.  A.  Mills.     Pericementitis.     [Missouri  Dent.  Jour.     1882.) 

A.   H.   Thompson.     Cases  of  Absorption  of  the  Eoots  of  Permanent  Teeth. 

[Archives  of  Dentistry.     1884.) 

W.  S.  Elliott.     Periodontitis,  etc.     [Dental  Cosmos.     Vol.  X.) 

H.  S.  Chase.     Periostitis.     [Dental  Cosmos.     Vol.  X.) 

M.  Dolbeau.     Absorption  of  Jaw.     [Dental  Cosmos.     Vol.  XL ) 

W.  H.  HowLAXD.     Maxillary  Absorption.     [Dental  Cosmos.     Vol.  XI.) 

M    A.  Spexcer.     Periostitis.     [Dental  Cosmos.     Vol.  XII.) 

W.  A.  Broxsox.     Peridentitis.     [Dental  Cosmos.     Vol.  XII.) 

V.   A.   Latham.      Diseases  of   the   Maxillary  Bones   and  their   Periosteum- 

[Dental  Cosmos.     Vol.  XXXA".) 

L.  Eequa.     Destroying  Pulps  with  Arsenic.     [Dental  Cosmos.    Vol.  XXXV.) 
M.  Stavely.     Case  of  Acute  Periostitis  of  the  .Jaw  from  Mercurial  Poisoning. 

[Dental  Cosmos.     Vol.  XXXV.) 

C.  Mayr.     The  Chemistry  of  Disinfectants  and  Antiseptics.     (Trans.   X.  Y. 

Odont  Soc.     1884.) 

G.  A.  Maxfield.     Alveolar  Absce^^s.     (Trans.  N.  Y.  Odont.  Soc.     1888  ) 
A.  C.  Hawes.     Exposed  Pulps  and   Alveolar  Abscess.     (Trans.    Am.    Dent. 

Ass.     1868.) 

S.  E.  KxowLES.    Alveolar  Abscess.    (Trans.  California  State  Dent.  Ass.    1886.) 
J.  31.  SuLLiVAX.      Alveolar  Abscess.      (Trans.   California   State   Dent.   Ass. 

1885.) 

C.    ScHMEDiCKE.      "Ubcr   die  Verzehrung  der    Zahnfiicher.       [Dcr   Zahnarzt. 

1851.) 

E.    Foucher.       tJber   einige   Varietiiten    der   am    Oberkiefer   vorkommenden 

Absce.<se.     [Der  Zahnarzt.     1857.) 

J.  P.  H.  Browx.     Alveolar  Abscess,  etc.     [Dental  Cosmos.     Vol.  I.) 

43 


642  LITERATURE. 

¥.  S(  iiNKiDEK.  I'yuriiio*!  der  Alveolen.  [Deut.  Vier.  Juhrsch.  f.  ZahnhtiLk. 
1875.) 

M.  ScHLENKEK.  Alveolar  Pyorrhoe.  {Deut.  Vier.  Jahrsch.  f.  Zahnhe'dk. 
1877.) 

—  Detznek.  Tod  duich  Pyaemie  in  Folge  von  Parulis.  [Beat.  Vier.  Jahrsc/i.. 
f.  Za/mhcllk.     1877.) 

J.  Jaegle.  Haemorrhagie,  Pyaemie,  und  Tod  in  Folge  eines  fungosen  Aus- 
wuchses  der  Pulpa,  etc.     {Deut    Vier.  Jahrsch.  f.  Zahnheilk.     1878.) 

C.  Gr.  JuNKERMAX.     Pyorrlicea  Alveolaris.     [Arch,  of  Dentistry.     1887.) 
C.  W.  Merry.     Pyorrlicea  Alveolaris.     [Ar-ch.  of  Dentistry.     1887.) 
Dr.  KiGGS.     Pyorrhoea  Alveolaris.     {Arch,  of  Dentistry.     1885.) 
J.D.Patterson.     Pyorrlicea  Alveolaris.     [A^xh.  of  Dentistry.     1885.) 
South.   Dental   Ass.      Pyorrhoea   Alveolaris.      [Arch,  of  Dentistry.      1885. 
Pp.  352  and  361.) 

K.  OTTOLENGtJi.     Pyorrhtea  Alveolaris.     (Arch,  of  Dentistry.     1889.) 
J.  W.  Miller.     Pyorrhcea  Alveolaris.     {Arch,  of  Dentistry.     1889.) 
M.  L.  Ehein.     Pyorrhoea  Alveolaris.     {Arch,  of  Dejitistry.     1889.) 
W.  Conrad.     PyoiThoea  Alveolaris.     {Arch,  of  Dentistry.     1889.) 
H.  Breslatjer.     On  Causes  of  Inflammation  of  the  Periosteum  of  the  Teeth. 
{Dental  Cosmos.     Vol.  II.) 

W.  H.  Atkinson.     Alveolar  Abscess.     {Dental  Cosmos.    Yds.  Ill  and  YIII.) 
G.  W.  Ellis.     Periodontitis.     {Dental  Cosmos.     Vol.  III.) 
W.  H.  Atkinson.     Alveolar  Abscess.     {Dental  Cosmos.     Vol.  IV.) 
C.  P.  Fitch.     Alveolar  Abscess.     {Dental  Cosmos.     Vol.  V.) 
J.  W.  Clowes.     Alveolar  Abscess      [Dental  Cos7nos.     Vol.  VI.) 
W.H.Atkinson.     Absorption  of  the  Alveoli.     {Dental  Cosmos.     Vol.  VII.) 
H.  S.  Chase.     Absorption  of  Dentine,  etc.     [Dental  Cosmos.     Vol.  VIII.) 
E.  "Williams.     Abscess  fi'om  a  Carious  Tooth.     [Dental  Cosmos.     Vol.  VIII.) 
F.Abbott.     Alveolar  Abscess.     {Dental  Cosmos.     Vol  XIV.) 

—  Maunder.     Acute  Abscess.     {Dental  Cosmos.     Vol.  XIV.) 

—  Bremer.     Alveolar  Absorption.     {Dental  Cosmos.     Vol.  XIV.) 

H.  Sewill.     Fistulous  Opening  on  the  Face.     {Dental  Cosmos.     Vol.  XV.) 
AY.  C.  Wardlaw.     Pericementitis.     {Dental  Cosmos.     Vol.  XVI. ) 
A.  W.  Barrett.     Decomposition  of  the  Dental  Pulp,  etc.     {Dental  Cosmos. 
Vol.  XVIII. ) 

C.  G.  Davis.     Gum  and  Alveolar  Diseases.     {Dental  Cosmos.     Vol.  XXI.) 

D.  H.  GooDwiLLiE.    Maxillary  Abscess,  etc     {Dental  Cosmos.   Vol   XXIII.) 

C.  J.  EssiG.  Some  of  the  Causes  of  the  Loss  of  the  Teeth  in  the  Adult. 
{Dental  Cosmos.     Vols.  XXII  and  XXIII.) 

G.  A.  Mills.     Some  of  the  Caiises  of  Loss  of  the  Teeth  in  the  Adult,  etc. 
{Dental  Cosmos.     Vol.  XXIII. ) 
H.  Cartwright.     Eiggs's  Disease.     [Dental  Cosmos.     Vol   XXIII.) 

D.  Hepburn.  Chronic  Suppuration  Connected  with  the  Teeth.  [Dental  Cos- 
nto.%     Vol.  XXIII.) 

H.  Sewill.  Alveolar  Periostitis  in  Diabetes  Mellitus.  [Dental  Costnos.  Vol. 
XXIV.) 

W.  H.  Atkinson.     Alveolar  Abscess      [Dental  Cosmos.     Vol.  XXV.) 

G.  H.  Mummery.  Alveolar  Abscess  of  Obscure  Origin.  [Dental  Cosmos. 
Vol.  XXVI.) 

J.  D.  Patterson.  The  Catarrhal  Xature  of  Pyon-hoea  Alveolaris  [Dental 
Cosmos.     Vol.  XXYII.) 


LITERATURE.  643 

A.  0.  IIa"W"ls.     Pyorrhoea  Alveolaris.     [Dental  Cosmos.     Yol.  XXVII.) 

—  Satjjtdbt.     Gouty  Teeth.     [Dental  Cosmos.     Vol.  XXVII.) 

E    S    Talbot.     Pyorrhoea  Alveolaris.     [Dental  Cosmos.     Vol   XXVIII.) 
N    Padley.     Pyorrhoea  Alveolaris.     [Dental  Cosmos.     Vol.  XXIX.) 

—  Edmuxds.     Pyon-hcea  Alveolaris  in  the  Elephant.     [Dental  Cosmos.     Vol. 
XXX  ) 

M    L    Khetx      Pyorrhoea  Alveolaris.     [Dental  Cosmos.     Vol.  XXX.) 

J.   D    PattePvSOX      Points  in  the  Etiology  of  Pyorrhoea  Alveolaris.     [Dental 

Cosmos.     Vol.  XXX  ) 
C    B.  Atkii«"so>"      Pyorrho3a  Alveolaris.     [Dental  Cosmos.     Vol.  XXXII.) 
J.  S    Marshall.     The  Kheumatic  and  Gouty  Diathesis,  etc.    [Dental  Cosmos. 

Vol  XXXIII.) 

"W    D    3I1LLEK.     Asepsis  and  Antisepsis  in  Practice.     [Dental  Cosmos.     Vol. 

XXXV. ) 

~W.  C.  Barrett.    Some  Thoughts  upon  Pyorrhoea  Alveolaris.    [Dental  Cosmos. 

Vol.  XXXV.) 

E.  L    Clifford.    Infection  fi-om  the  Mouth.    [Dental  Cosmos.    Vol.  XXXV.) 

G    Netvkirk.     Antiseptic  Dentistiy.     [Dental  Revieic.     1892.) 

"W.    L.    Jermax.      Eeports   on   Pyorrhoea   Alveolaris,   etc.     [Denial  Revieic. 

1891.) 

Mr.  Sta>*ley.    Periostitis  of  Upper  Jaw,  etc.    [Am.  Jour,  oj  Dent.  Sci.    1850.) 

C.  Bew.     Alveolar  Abscess.     [Am.  Jour,  of  Dent.  Sci.     1851.) 

J.  M.  EiGGS.     Suppurative  Inflammation  of  the  Gums,  etc.     [Penn.  .Tour,  of 

Dent.  Sci.     1876.) 
J.  Reqxja.     Dental  Periostitis.     [Indep.  Pract.     1883.) 
W.  D.  Miller.     Proliferation  of  Epithelium  in  an  Alveolar  Abscess.    [Indep. 

Pract.     1885.) 

A.  E.  Starr.     Pyon-hoea  Alveolaris.     [Indep.  Pract.     1886.) 

J.  N.  Farrar.     Loculosis  Alveolaris.     [Indep.  Pract.     1886.) 

G.  A.  Maxfield.     Alveolar  Abscess.     [Indep.  Pract.     1887.) 

E.  B.  Adair.     Alveolar  Abscess.     [Indep.  Pract.     1889.) 

J.  Head.     Alveolar  Abscess.     [Indep.  Pract.     1889.) 

W.  H.  Trvemax.     Intentional  Devitalization  of  the  Dental  Pulp.     [Intern. 

Dent.  Jour.     1889.) 

E.  C.  Kirk.     Alveolar  Abscess.     [Intern.  Deni.  Jour.     1889.) 

G.  S.  Allax.     Pyon-hoea  Alveolaris.     [Intern.  Dent.  Jour.     1889.) 

E.  F.  Stevejs's.     Pyon-hoea  Alveolaris.     [Intern.  Dent.  Jour.     1892.) 

C.  JN".  Peirce.     Pyorrhoea  Alveolaris.     [Intern.  Dent.  Jour.     1892.) 

J.  M.  Potter.     Pulpless  Teeth  :  Abscess.-    [Intern.  Dent.  Jour.     1892.) 

E.  C.  Kirk.     Alveolar  Abscess.     [Intern.  Dent.  Jour.     1892.) 

H.    A.    Kelley.      a  Study  of  the   Diseases  of   the   Peridental   ^Membrane. 

[Intern.  Dent.  Jour.     1893.) 
G.  A.  Mills.     Eiggs's  Disease.     [Intern.  Dent.  Jour.     1893.) 

.     Alveolar  Absorption.     [Mis sotiri  Dent.  Jour.     1869.) 

T.  EoTTX.     Observations  de  fistules  dentaires  remarquables  par  I'obscurite  du 

diagnostic  et  la  gravite  des  lesions  consecutives.     [Bull.  gen.  d.  Chirug.,  Aout.  15.) 
E.  Magitot.     Odontalgic.     Diet,  encycl.  d.  Sc.  Medic.     Tome  XIV. 

—  Pietkiewicz.     Des  fistules  dentaires.     [Gaz.  des  Hop.     1874.) 

—  EiCHAiXD.     Essai  sur  les  fistules  in  Jahrb.  Virch-Hirsch.     1877. 

E.  DEMA^"GE.     Chute  spontanee  des  dents  et  crises  gastriques,  etc.     [Rev.  de 
Med.     1882.) 


64-i  LITERATURE. 

—  DoLBEAt'.  Affection  singuliere  du  maxill.  sup.  caracterisee  surtout  par  la 
disparitiou  du  bord  alveolaire.     [Gaz.  des  Hop.     1869.) 

E.  Magitot.  Kapport  sur  la  pathogenie  et  traitem.  de  la  gingivite  expulsive. 
[Bull.  Soc.  de  Ghirurci.     1880.) 

A.  DE  Sadra:s".  Pathogenie  et  traitem.  de  la  gingivite  expulsive.  {BuU.  cl.  I. 
Soc.  de  Chir.     1880.) 

J.  Israel.  ]S'eue  Beobachtungen  auf  dem  Gebiete  der  Mykosen  des  Menschen. 
(^Virch.  Ay^eh.     BdLXXIY.     1880.) 

C.  S.  Tomes.     In  Trans.  Odont.  Soc.  |Gr.  Britain.     1883.     Pp.  4  and  5. 

J.  EiCHAKDSox.  Eeflex  Lesions  of  the  Oral  Cavity  associated  with  Pregnancy. 
{British  Journal  of  Dental  Science.     1882.) 

C.  S.  Tomes.  On  Premature  Loss  of  the  Teeth.  {Monthly  Review  of  Dental 
Surgery.     1874.) 

A.  ScHELLER.  tJber  Alveolarabsorption  und  Behandlung  derselben.  [Deut. 
Vier.  Jahrschr.  f.  Zahnheilk.     1871.) 

—  Vallix  and  Luts.  The  Loosening  of  the  Teeth  in  Ataxy.  {Dental 
Cosmos.     Vol.  XXIII.) 

T.  Davis.  Lesions  of  the  Teeth  in  Locomotor  Ataxy.  {Dental  Cosmos.  Vol. 
XXIV.) 

J.  Parreidt.  Periostitis  Alveolo-Dentalis  Idiopathica.  {Deut.  Vier.  Jahrsch. 
f.  Zahnheilk.     1880.) 

G-.  V.  Black.  Diseases  of  the  Peridental  Membrane.  (American  System  of 
Dentistry.     Philadelphia,  1886.) 

P.  Bros.  Ein  Fall  von  Periostitis  alveolaris  Maxilla?  inferioris  mit  todtlichem 
em  Ausgange.     {Drat.  Mouatssch.f.  Zahnheilh.     1883.) 

J.  Parreidt.  Zahnfistel  in  Folge  eines  iiberstandenen  Typhus.  {Dent. 
Monatssch.f.  Zahnheilk.     1883.) 

—  Wallauer.  IJber  vereinzelt  auftretende  Verkiimmerungen  der  Prae- 
molaren  beim  Menschen  als  Eolge  acuter  und  chronischer  Eiterung  der  Milch- 
molaren.     {Deut.  Monatssch.  f.  Zahnheilk.     1885.) 

—  EoBiscEK.  Wesen  und  Behandlung  der  Alveolarpyorrhoe.  {Deut.  Monatssch. 
f.  Zahnheilk.     1885.) 

J.  ScHEFF,  Jr.     Zur  Differentialdiagnose   der   Zahnfleisch-T\rangenfii?tel,   etc. 

{Deut.  Monatssch.  f.  Zahnheilk.     1887.) 

G-.  P.  Geist.     Pyorrhoea  Alveolaris.    {Dent.  Monatssch.  _f.  Zahnheilk.     1891.) 
A.  PiLLiET.     Double  suppuration  des  glandes  sous-maxillares.     {Bullet,  de  la 

Soc.  anat.  de  Paris.,  7.     1891.) 

—  Hattyasi.     Oest.  Ung.  Vier.  Jahrsch.  f.  Zahnheilk.     1890.     No.  3. 
Ed.  Nessel.     Oest.  Ung.  Vier.  Jahrsch.  f.  Zahnheilk.     1888.     No.  4. 

—  Schnitzler.     Beitr.  zur  Casuistik  der  branchiogeneii  Fisteln.     Wien,  1890. 
L.  Hollaestder.     Drei  Falle  aus  der  Praxis.     {Oest.    Ung.  Vier.  Jahrsch.  f. 

Zahnheilk.     1886.) 

A.  WiTZEL.  Pyorrhoea  Alveolaris.  ( Oest.  Ung.  Vier.  Jahrsch.  f.  Zahnheilk. 
1881.) 

—  EoBiscEK.  Pyorrhoea  Alveolaris.  {Jahrb.  der  Ver.  Oest.  Zahnarzte  1883- 
84.) 

J.  "Walker.  On  the  Premature  Loss  by  Destruction  of  the  Alveoli.  (Trans. 
Intern.  Med.  Congress.     London,  1881.) 

—  Ballerio.     Eesorption  d.  Zahnfaches.    {Correspond,  f.  Zahnarzte.    1883.) 

D.  Duckworth.  The  Characters  of  the  Teeth  in  Peraons  of  the  Arthritic 
Diathesis.     (Trans.  Odont.  Soc.  Gr.  Britain.     1883.) 


LITERATURE.  645 

—  FiciNUS.  tJber  das  Ausfallen  der  Ziihiie.  {Walter' sund  Amnion^  s  Jour.  f. 
Chlrurrjie.     1847.) 

—  T.  Beegmaxx.  Erkrankungen  der  Lymphdriiseu.  (Gerhard's  Handb.  d. 
Kinderkrankh.     Bd.  VI.) 

—  A\  Tadex.  Tiefe  Abscesse  am  Kieferwinkel.  (Mittla.  f.  d.Yerein  Schlesw. 
Hoist   Artze.  in  Jahrb.     1872.) 

—  AuBrKTix.     Essai  sur  les  kystes  dentaires.     Paris,  1874. 

—  EosEXBACH.  Zur  keuiitniss  der  Strahlenpilzerkrankuugen  beim  ^lenschen. 
(Centralhl.  f.  Chirurgle.     1880.) 

P.  Kraske.  tJber  eine  wahi'scbeinlich  inykotiscbe  Aft'ectitm  der  Kiefer- 
knocben.     {Arch.f.  Klin.  Chirurgie.     1880.) 

E.  Albert.     Diagnostik  der  chirurgiscben  Krankbeiten.     Wien,  1885. 

J.  K,.  Bate.     Alveolar  Abscess.    \Monthly  Review  of  Dental  Surgery.     1883.) 

D.  Hepburx.  On  Chronic  Suppuration  Connected  with  the  Teeth.  (Trans. 
Odont.  Soc.  Gr.  Britain.     1880.) 

E.  Magitot.  Eecent  Eesearches  on  Syiiiptiimatic  Alveolar  Arthritis.  (Trans. 
Odont.  Soc.  Gr.  Britain.     1887.) 

F.  IST.  Pedlet.  On  the  Pathology  of  Eiggs's  Disease  or  PyoiThcea  Alveo- 
laris.     (Trans.  Odont.  Soc.  Gr.  Britain.     1887.) 

E.  L.  Williams.  The  Pathology  of  Alveolar  Abscess.  (Trans.  Odont.  Soc. 
Gr.  Britain.     1888.) 

0.  Coles.  On  the  So-called  Eiggs's  Disease.  (Trans.  Odont.  Soc.  Gr.  Britain. 
1877.) 

W.  J.  FisK.     Pyorrhoea  Alveolaris.    {British  Journal  of  Dental  Science.    1892.) 
C.  N.  Peirce.    Etiology  of  Pyorrhcea  Alveolaris.    {Intern.  Dent.  Jour.    1894.) 

F.  T.  Van  "Woert.     Pyorrhcea  Alveolaris.     {Intern.  Dent.  .Jour.     1894.) 

G.  S.  Allax.     Pyorrhoea  Alveolaris.     {Intern.  Dent.  Jour.     1894.) 
J.  Truman.     Pyon-hoea  Alveolaris.     {Intern.  Dent.  Jour.     1894.) 

E  E.  Andrews.     Pyon-hoea  Alveolaris.     {Intern.  Dent.  Jour.     1894.) 
S.  H.  GuiLFOED.     Pyorrhoea  Alveolaris.     {Intern.  Dent.  Jour.     1894.) 
M.  L.  Ehein.     PyoiThoea  Alveolaris.     {Intern.  Dent.  Jour.     1894.) 
A.  P.  Brtjbaker.     Pyorrhcea  Alveolaris.     {Intern.  Dent.  .Tour.     1894.) 
E.  T.  Darby.     Pyorrhoea  Alveolaris.     {Intern.  Dent.  Jour.     1894.) 
E.  Ottolengtji.     Pyorrhoea  Alveolaris.     {Intern.  Dent.  Jour.     1894.) 

—  Tinker.  Pyorrhoea  Alveolaris  in  Domesticated  Animals  (Panther,  Kan- 
garoo, Dog,  Ape).     {Oclontogr.  Jour.     1894.) 

W,  X.  SuDDiTTH.     Pyorrhoea  Alveolaris.     {Dental  Cosmo.^.     Vol.  XXXVI.) 
C.  Jung.  Die  Erkrankungen  der  Wurzelhaut  des  Zabns,  etc.   {Deut.  Monatsschr. 
f.  Zahnheilk.     1894.) 

—  Pedley.     On  the  Pathology  of  Eiggs's  Disease.     {Dental  Record.     1887.) 
V.  Mettxitz.    Ein  Fall  von  acuter  Osteomyelitis  des  Unterkiefers  mit  todtlich- 

em  Ausgange.     {Oestr.  Ung.  Vier.  Jahrschr.  f.  Zahnheilk.     1887.) 

G.  D.  Pollock.  Alveolar  Abscess  Dependent  on  Diseased  Teeth.  (Trans. 
Odont.  Soc.  Gr.  Britain.     1876.) 

H.  MosER.  Two  Cases  of  Periostitis  of  the  Upper  Jaw  in  Close  Eelationship 
to  Iniiuenza.     {British  Journal  of  Dental  Science.     1890.) 

J.  Maughan.  a  Case  of  Extended  Alveolar  Abscess.  {B'ritish  Journal  of 
Dental  Science.     1893.) 

M.  Heide.  a  Cutaneous  Fistula  of  Dental  Origin.  {British  Journal  of 
Dental  Science.     1893.) 


646  LITERATURE. 

CHAPTEEXL. 

W.  D.  Miller.  The  Micro-Organisms  of  the  Human  Mouth.  Philadelphia, 
1890. 

J.  C.  Steahl.  tJber  den  Influss  der  Sauren  auf  die  Zahne.  {De?-  Zahnarzt. 
1846.) 

R.  PiciKTJS.  titer  das  Ausfallen  der  Ziihne,  und  das  Wesen  der  Zahnkaries. 
(Der  Zahnarzt.     1847.) 

J.  Bruck.     Die  Ursachen  der  Zahnverderbniss,  etc.     {Der  Zahnarzt.     1852  ) 

—  Bauer.     Betrachtungen  liber  die  Karies  der  Zahne.    {Der  Zahnarzt.    185..) 

—  Rossi.     tJber  die  Yerderbniss  der  Ziihne.     {Der  Zahnarzt.     18')2  and  1853.) 
V.  PiATJLT.     tlber  die  Karies  der  Zahne.     {Der  Zahnarzt.     1861.) 

—  ScHROTT.  Die  Be wohner  des  Mundes  und  der  Zahne.  {Deut.  Vier.  Jahrschr. 
f.  Zahnheilk.     1868.) 

J.  LiNDEEER.    Die  innere  Caries.     {Deut.  Vier.  Jahrschr.  f.  Zahnheilk.    1873.) 
E.  MtJHLREiTER.     Die  Natur  der  anomalen  Hohlenbildung  im  Oberen  Seiten- 

schneidezahn.     {Deut.  Vier.  Jahrschr.  f.  Zahnheilk.     1873.) 

Gc.  Y.  Black.    Dental  Caries.    (American  System  of  Dentistry.    Philadelphia, 

1886.) 

—  Brunsman.  Uber  Progressive  Zahnverderbniss.  {Deut.  Monatssch.  f.  Zahn- 
heilk.    1885.) 

E.Hesse.     Zahnkaries  bei  Backern.     {Deut   Monatssch.  f.  Zahnheilk.     1886.) 

"W.  K.  Bridgeman.  On  Caries  and  its  Treatment.  (Trans.  Odont.  Soc.  Gr. 
Britain.     1861.) 

W.  K.  Bridgeman.  On  the  Pathology  of  Dental  Caries.  (Trans.  Odont.  Soc. 
Gr.  Britain.     1861.) 

C.  S.  Bate.  Pathology  of  Dental  Caries.  (Trans.  Odont.  Soc.  Gr.  Britain. 
1864.) 

E.  W.  EotrGHTON.  The  Micro-Organisms  of  the  Mouth.  {British  Journal  of 
Dental  Science.     1893.) 

H.  Sevtill.  The  Artificial  Production  of  Dental  Caries.  (Trans.  Odont.  Soc. 
Gr.  Britain.     1890.) 

C.  S.  BoYNTOiv.  Role  of  Bacteria  Fermentation,  etc.  {New  England.  Journal 
of  Dentistry.     1883.) 

C.  Mate.  Chemical  Composition  of  Decayed  Dentine.  {New  England  Journal 
of  Dentistnj.     1883.) 

C.  S.  BoTNTON.  Germ  Theory  Mortally  Wounded.  {New  England  Journal 
of  Dentistry.     1883.) 

A.  S.  Underwood.  On  the  Influence  of  Micro-Organisms  in  the  Production 
of  Caries.     {Neio  England  Dental  Journal.     1884.) 

C.  S.  BoYNTON.     Bacteria.     {Neic  England  Dental  Journal.     1884.) 

E.  Searle.  The  Septic  Theory  of  Dental  Caries.  {Neiv  England  Dental 
Journal.     1884.) 

F.  Y.  Claek.  Which  was  First — the  Hen  or  the  Egg,  the  Bug  or  the  Acid  ? 
{New  England  Journal  of  Dentistry.    1884.) 

G.  Y.  Black.     Dental  Caries,  etc.     {Archives  of  Dentistry.     1885.) 
A.  L.  LooMis.     Bacteriology.     {Archives  of  Dentistry.     1885.) 

J.  M.  RiGGS.     On  Dental  Caries.     {Archives  of  Dentistry .     1885.) 

H.  Sewill.     Dental  Caries,  etc.     {Archives  of  Dentistry.     1885.) 

E.  R.  Smilie.     Dental  Caries.     {Dental  Cosmos.     Yol.  YIII.) 

J.  PiDDUCK.     Dental  Caries.     {Dental  Cosmos.     Yol.  YIII.) 

M.  BiscHorr.     Dental  Caries  in  the  Ape.     {Dental  Cosmos.     Yul.  \MIL) 


LITERATURE.  647 

J.  P.  H.  Bkown.     Cause  of  Caries  in  Teeth.     i^Dtidul  CuHinus.     Vol.  X.) 
C.  S.  Weeks.     Causes  of  the  Decay  of  Teeth.     {Dental  Cosmos.     Vol.  X.) 
G.  J.  ZiEGLER.     Dental  Caries,  etc.     [Dental  Cosmos.     Vol.  XII.) 
J.  Beudoe.     Dental  Caries.     [Dental  Cosmos.     Vol.  XIII.) 
S.  E.  Knowles.     Pathology  of  Caries.     [Dental  Cosmos.     Vol.  XV.) 
C.   N.  Peirce.     \i\  Essay  on  the  Lower  Forms  of  Life,  etc.     ( Dental  Cosmos. 
Vol.  XVII.) 

T.  C.  Stellwagen.     Dental  Caries.     [Dental  Cosmos.     Vol.  XVII.) 

F.  Abbott.     Caries  of  Human  Teeth.     [Dental  Cosmos.     Vol.  XXI. ) 
J.  D.  Clark.     Caries  of  the  Teeth.     [Dental  Cosmos.     Vol.  XXIII.) 

H.  Gerhart.  Primal  Cause  of  Dental  Caries.  [Dental  Cosn/ws.  \'n\. 
XXIIL) 

B.  W.  Richardson.  On  the  Origin  of  Dental  Caries.  [Dental  Cosmos.  Vol. 
XXIV.) 

G.  P.  EiSHEL.     Dental  Caries.     [Dental  Cosmos.     Vol.  XXIV.) 

—  SiTHERWooD  and  Haklan.  Cerebral  Origin  of  Dental  Decay.  [Dental 
Cosmos.     Vol.  XXV.) 

H.  Sewill.     Dental  Caries.     [Dental  Cosmos.     Vol.  XXV.) 

—  Carpenter.     Causes  of  Dental  Decay.     [Dental  Cosmos.     Vol.  XXV.) 
W.  D.  Miller.     Agency  of  Micro-Organisms  in  Decay  of  the  Human  Teeth. 

[Dental  Cosmos.     Vol.  XXV.) 

"W.  D.  Miller.  The  Agency  of  Acids  in  the  Production  of  Caries  of  the 
Human  Teeth,  with  Comparative  Analysis  of  Carious  Dentine  and  Dentine  Soft- 
ened by  Acids.     [Dental  Cosmos.     Vol.  XXV.) 

C.  N.  Peirce.  Calcification,  Decalcification,  Absorption,  Hypertrophy. 
[Dental  Cosmos.     Vol.  XXV.) 

A.  MoRSMAN.    Dental  Caries.     [Denial  Cosmos.    Vols.  XXVII  and  XXVIII.) 
V.  Galippe.     The   Influence   of   Sex   on   the   Frequency   of  Dental   Caries. 

[Dental  Cosm.os.     Vol.  XXVII.) 

W.  X.  SuDBUTH.     Is  Decay  of  the  Teeth  an  Inflammatory  or   a  Chemical 

Action?     [Dental  Cosmos.     Vol.  XXVIII.) 

A.  Gysi.    Dental  Caries  under  the  Microscope.    [Dental  Cosmos.    Vol.  XXIX.) 
G.  V.  Black.     An  Examination  of  the  Physical  Forces  with  Reference  to  the 

Germ  Theory,  etc.     [Dental  Cosmos.     Vol.  XXX.) 
L.  Ottoft.    The  Incipiency  of  Dental  Caries.     [Dental  Cosmos.    Vol.  XXXI  ) 

E.  P.  Beadles.  The  Bacteria  of  the  Human  Mouth.  [Dental  Cosmos.  Vol. 
XXXIV.) 

H.  Block.     The  Causes  of  Dental  Caries.     [Dental  Cosmos.     Vol.  XXXV.) 
S.  B.  Palmer.    Dental  Decay,  etc.    [Denial  and  Oral  Science  Mnf/azinr.    1878.) 

F.  T.  Clark.     Bacteria.     (Trans.  N.  Y.  Odont.  Soc.     1881.) 

G.  S    Allan.     Caries  of  the  Teeth.     (Trans.  N.  Y.  Odont.  Soc.     1886.) 

J.  Cheesebrough.     Sympathetic   Relations   of  the  Teeth  with  the  Viscera. 

(Trans.  Am.  Dent.  Ass.    1865.) 

C.  Tomes.     A  Cause  for  Dental  Caries,     [Johnston^ s  Dental  Miscellany.     1878.) 
E    Noyes.     The  Etiology  of  Dental  Caries.     [Dental  Review.     1890.) 
G    V    Black.     Fermentation  and  Putrefaction.     [Dental  Review.     1890.) 
F    H.  Rehwinkel.     Caries   of  the   Teeth,    etc.     [Am.    Jour,    of  Deyit.    Sci. 

1855.) 

J.  Taft.     Caries  of  the  Teeth.     [Am.  Jour,  of  Dent.  Sci.     1856.) 

A.  F.   McLain.     Causes  of  Decay  in  Human  Teeth.     [Penn.  Jour,  of  Dent. 

Sci.     1874.) 


648  LITERATURE. 

C.  N.  Peiece.     Lower  Forms  of  Life,  etc.     [Penn.  Jour,  of  Dent.  Sci.     1876.) 
C.  jN".  Peiece.     Dental  Caries.     {Penn.  Jour,  of  Bent.  Sci.     1876.) 

F.  Y.  Claek.     Bacteria  the  Cause  of  Caries.     (Indep.  Pract.     1882.) 
J.  S.  Dodge.     Senile  Decay.     {Indep.  Pract.     1884.) 

W.  D.  Millee.     Absorption  of  Dentine,  etc.      {Indep.  Pract.     1887.) 

G.  P.  EiSHEL.    Causes  and  Treatment  of  Dental  Caries.    {Indep.  Pract.     1887.) 

F.  Abbott.     On  Caries.     {Indep.  Pract.     1889.) 

E.  Laplace.     Fermentation,  etc.     {Indep.  Pract.     1890.) 

J.  N.  Ceouse.     Dental  Caries.     {Missouri  Dent.  Jour.     1869.) 

E.  C.  Edsill.     Why  do  the  Teeth  Decay  ?     {Missouri  Dent.  Jour.     1869.) 

J.  M.  Whitney.     Is  Dental  Caries   the  Eesult   of  Civilization?     {Missouri 

Dent.  Jour.     1872.) 

R.  CuTTEE.     Does  the  Use  ot  Flour  Promote  Decay  of  the  Teeth  ?     {Missouri 

Dent.  Jour.     1874.) 

W.  K.  Beidgeman.     Dental  Caries.     {Missouri  Dent.  Jour.     1878.) 
S.  M.  Peotheo.     Caries.     {Missouri  Dent.  Jour.     1879.) 

G.  Y.  Black.     Caries  of  Teeth.     {Missouri  Dent.  Jour.     1880.) 

C.  T.  Stockwell.     Etiology  of  Dental  Caries.     {Missouri  Dent.  Jour.     1882.) 

C.  W.  Spatjlding.  Suggestion  Relative  to  the  Cause  of  Rapid  Dental  Decay. 
{Missouri  Dent.  Jour.     1882.) 

C.  T.  Stockwell.  Etiology  of  Dental  Caries.  {New  England  Jour,  of  Dent. 
1882.) 

C.  T.  Stockwell.  Micro-Organisms,  the  Essential  Factor  in  Dental  Caries. 
{New  England  Jour,  of  Dent.     1883.) 

E.  W.  RouGHTON.  The  Micro-Organisms  of  the  Mouth.  (Trans.  Odont.  Soc. 
Gr.  Britain.     1893.) 

C.  A.  Hayjian.  The  Physiology  and  Pathology  of  Dental  Caries.  {Monthly 
Revieio  of  Dental  Surgery.     1881.) 

P.  DiETEiCH.  Bacteriologie  in  Handh.  der  Zahnheilk.  von  J.  Scheff,  jr.  Wien, 
1891. 

M.  Bastye.     Ziebni  lekarstoi,  I.     S.  249. 

M.  Bastye.     Casopis  ceskyeh  lekaru,  XXII.     1883.     S.  318. 

F.  Wallauee.  Caries  der  Zahne  in  Handb.  der  Zahnheilk.  von  J.  Scheff,  jr. 
Wien,  1891. 

E.  Magitot.     Treatise  on  Dental  Caries.     Boston,  1878. 

W.  D.  Millee.  Die  Mundhohle  als  Infectionsherd.  {Deut.  Monatssch.  f. 
Zahnheilk.     1892.) 

R.  Telschow.     Die  wahren  Uhrsachen  der  Zahncaries,  etc.     Berlin,  1892. 

R.  HoPPE.     Mundbakterien.     [Deut.  Monatsschr.  f.  Zahnheilk.     1893.) 

C.  JrxG.     ITntersuchungen  iiber  die  Bakterien  der  Zahncaries.     Berlin,  1892. 

E.  jSTeumax.     tiber  das  Wesen  der  Zahnverderbniss. 

A.  Caepentee.  a  Consideration  of  Some  of  the  Cavises  which  Give  Rise  to 
Dental  Decay.     {Br.  Jour,  of  Dent.  Sci.     1883.) 

R.  H.  MooEE.  Dental  Caries  as  a  Result  of  Inflammation  of  the  Dentine. 
{Brit.  Jour,  of  Dent.  Sci.     1889.) 

G.  W.  Watson.  The  Micro-Organisms  of  the  Mouth  and  their  Association 
with  Disease.     {Brit.  Jour,  of  Dent.  Sci.     1889.) 

J.  H.  MiTMMEEY.  On  the  Action  of  Micro-Organisms  in  Caries  of  the  Teeth. 
{Brit.  Jour   of  Dent.  Sci.     1890.) 

A.  Caepentee.  A  Consideration  of  Some  of  the  Causes  which  Give  Rise  to 
Dental  Caries.     (Trans.  Odont.  Soc.  Gr..  Britain.     1882.) 


LITERATURE.  649 

—  De  Bary.     Vergl.  Morphologie  unci  Biologie  der  Pilze.     S.  490. 

—  Flugge.     Die  IMikroorganisinen.     Leipzig,  1886.     S.  76. 

—  Frank.  Leuuis'  Synopsis  der  drei  Natiureiclie.  Bd.  III.  Specielle 
Botanik,  Kryptogamen.     S.  842. 

—  ZoPF.     Die  Spaltpilze.     S.  1. 

CoRNiL  et  Babes.     Les  Bacteries.     P.  173. 

—  Ehrekberg.  Organisation,  Systematik  und  geographisches  Verhaltniss  der 
Infusionsthierchen.  Berlin,  1830.  Die  Infusionsthierchen  als  vollkommene 
Organismen.     Leipzig,  1838. 

—  Lettwenhoek.  Opera  omnia  sive  arcana  naturaj  ope  microscqpiorum 
exactissimorum  detecta.     1722. 

—  Nencki.     Beitriige  zur  Biologie  der  Spaltpilze.     1880. 
CoHN  und  Mendelsohn.     Cohn's  Beitrdge.     Bd.  Til,  Heft  1. 

—  Miller.  Ueber  Gahrungsvorgange  im  Yerdauungstractus  und  die  dabei 
betheiligten  Spaltpilze.     [Deutsche  Med.  Woehenschr.     1885.     No.  49. ) 

—  Flugge.     Die  Mikroorganismen.     Leipzig,  1886. 

—  Pasteur.     Annalos  de  Chimie  et  Physiologie.     1867. 

—  Hueppe.  Ueber  die  Zersetzung  der  Milch.  [Mitth.  a.  d.  Reichsgesundheitsamt. 
Bd.  II,  S.  307.) 

—  Black.  Gelatine-Forming  Micro-Organisms.  [Independent  Practitioner, 
1886.     P.  546) 

—  Prazmowski.  Untersuchungen  iiber  die  Entwickelung  und  Fermentwir- 
kung  einiger  Bacterienarten.     Leipzig,  1880. 

—  Brieger.  Ueber  Spaltuugsproducte  der  Bacterien.  [Zeitschr.  f.  physiol. 
Chemie.     Bd.  YIII,  Heft  4  und  Bd.  IX,  Heft  1.) 

—  FiTZ.  Beriehte  der  Chem.  Gescll.  1873,  Bd.  VI,  S.  48;  1876,  Bd  IX,  2, 
S  1348;  1878,  Bd.  XI,  S.  42  ;  1879,  Bd.  XIT,  1,  S.  374;  1880,  Bd.  XIII,  1,  S. 
1309;  1882,  Bd.  XV,  1,  S.  867;  1888,  Bd.  XVI,  S.  844;  1884,  Bd.  XVII.  S 
1189. 

—  BouTROUX.  Surlafennentation  lactique.  [Comptes  rendus.  Bd.  LXXXVI, 
P.  605.     1878.) 

—  Flugge.     Die  Mikroorganismen.     S.  486. 

—  Nencki.  Ueber  die  Zersetzung  der  Gelatine  und  des  Eiweisses  bei  der  Faul- 
niss  u.  s.  w.     Bern,  1876. 

—  Hansen.  Contributions  a  la  connaissance  des  organismes  qui  peuvent  se 
trouver  dans  la  biere  et  la  mout  de  biere  et  y  vivre.  {Meddelser  fra  Carlsberg- 
laboratoriet.     1879.     Heft  2.)  • 

Schlosing  und  Muntz.  Cow.pites  rendus.  Bd.  LXXXIX.  Pp.  891  et  1074  ; 
Bd.  LXXXIV,  P.  301  ;  Bd  LXXVII,  Pp.  203,  353. 

Gayon  et  DuPETiT.     Compies  rendus.     1882.     Bd.  XCV,  Pp.  664,  1365. 

Deherain  et  Maquenne.  Sur  la  reduction  des  nitrates,  etc.  {Comptes  rendus. 
1882.     IL     Bd.  XCV,  Pp.  691,  732,  854  ) 

—  Heraeus.  Ueber  das  Verhalten  der  Bacterien  im  Brunnenwasser.  (Zeitsc/ir. 
f.  Hygiejie.     Bd.  I.) 

—  Warrington.     Journal  of  the  Chem.  Society.     August,   1888.     P.  727. 

—  BiNZ.     Arzneimittellebre.     S.  197,  198. 
LiBORius,  Flugge.     Die  Mikroorganismen.     S.  455. 

Ellenberger  und  Hofmeister.  Der  Speichel  der  Wiederkauer.  {Bericht 
iiber  das  Veterinarwesen  im  Kbnigreich  Saehsen.     1885.     S.  119.) 

Ellenberger  und  Hofmeister.  Die  Function  der  Speicheldriisen  der 
Haussaugethiere.     [Archivf.  wissench.  u.  ptrakt.  Thierheilk.     11.     1885.) 

44 


650  LITERATURE. 

—  Hermakx.     Physiologie.     S.  94. 

—  Leuwenhoek.     Opera  omnia,  etc.     Bd.  II,  S.  40,  1722. 

—  Mandl.     Compte.-:  renclus  hebcl.  des  Seauces  de  I'Academie  des  Sciences. 
Bd.  XVII,  P.  213. 

—  BtJHLMAKN.     Miiller's  Archiv  f.  Anatomie.     1840. 

—  Henle.     Pathologisclie  Untersuchungen.     1840. 

—  Ekdl.      Allgemelne  Zeitiing   f.   Chlrurgie   von  Rohatzsch.      1843.     No.  19. 
S.  159. 

—  EoBix.     Histoire  naturelle  des  vegetaux  parasites.     1863. 

—  EoBiiv^.     Des  vegetaux  qui  croissent  sur  les  animaux  vivants.     Paris,  1847. 
P.  42. 

— .  Klencke.     Die  Verderbniss  der  Zahne.     Leipzig,  1850. 

—  Hallier.     Die  pflanzlichen  Parasiten,  etc.     Leipzig,  1866. 
Leber  und  Eottenstein.     Ueber  d   Caries  der  Zahne.     Berlin,  1867. 

—  ViGNAL.     Eecherches  sur  les  Microorganismes  de  la  bouche.     {Archives  de 
physiol.  norm,  et  jMthol.     1886.     No.  8.) 

—  Miller.     Zur  Kenntniss  der  Bakterien  der  Mundholile      [Deutsche  Med. 
Wochenschr.     1884.     No.  47.) 

—  Lewis.     Lancet.     September,  1884. 

—  Miller.     Ueber  einen  Zahn-Spaltpilz,  Leptothrix  gigantea.     {Berichte  der 
Bothnischen  Gesellschaft.     1883.     S.  224.) 

—  Miller.     Biological  Studies  on  the  Fungi  of  the  Human  Mouth.     [Indep. 
Practitioner.     1885.     Pp.  227,  283.) 

—  Black.     Trans,  of  111.  State  Dental  Society.     1886. 

—  Watt.     Chemical  Essays. 

—  YiGSTAL      La  France  9nedicale.     Aout  25,  1887. 

—  Hueppe.     Deutsche  Med.  Wochenschr.     1884.     Nos.  48,  49. 

—  EscHERiCH.     Die  Darmbacterien  des  Siiuglings.     1886. 

—  Baginskt.     Deutsche  Med.  Wochenschr.     1888.     No.  20. 

—  Kratjtermann.     Sicherer  Augen- und  Zahnarzt.     1732. 

—  BoUBDET.     Becherches  et  observations  sur  toutes  les  parties  de  I'art  du  den- 
tiste.     1757.     P.  95. 

—  ScHLEXKER.     Die  Verderbniss  der  Zahne. 

—  V.  Carabelli.     Handbuch  der  Zahnheilkunde. 

-—  Ettstachius.     Opuscula  anatomica  et  de  dentibus.     1574. 
Prank    Abbott.     Caries    of   the    Human    Teeth.     [Dental    Cosmos.     1879. 
February,  March,  April.) 

C.  Heitzmaxjj.     New  England  Journal  of  Dentistry.     Vol.  I,  P.  193. 

—  Fauchard.     Le  chirurgien-dentiste.     Paris,  1728,  1746,  1786. 

—  Pfaef.     Abhandlung  von  den  Zahnen.     1756. 

W  EoBERTSOisr.     A  Practical  Treatise  on  the  Human  Teeth,  etc.     1836. 

—  EoGNARD.     Gaz.  des  Hopit.     1838. 

—  Magitot.     La  salive.     Paris,  1867. 

—  Magitot.     Etudes  et  experiences  sur  la  salive.     Paris,  1867. 
MiLLES  and  Uxderwood.     Trans.  Intern.  Med   Congr.     1881. 

Ad.  Weil.     Vortrage,  gehalten  zu  Miinchen  in  der  Sitzung  des  arztlichen 
Vereins.     1880.     S.  187. 

—  Bastye.      Oesterreichisch-Ung.    Viertel]ahrsse]ir.  f.     Zahnheilk.      1885-86. 
S.  355. 

—  Miller.     Denial  Cosmos.     1881.     P.  91. 

—  Magitot.     Eecherches  sur  la  carie  des  dents.     1871. 


LITERATURE.  651 

—  Miller.  Einfluss  der  Mikroorgaiiisinen  auf  die  Caries  der  mt'nsclilichen 
Zahue.     [Arc/iirfii}-  e.rjje)'l»ie/ifclle  Paf/iolof/ie.     Bd.  XVI.     1882.) 

MiLLEs  and  Uxdekwood.      Trans,  of  the  Odont.  Soc.  of  Great  Brita'ni.     1884. 

P.  Tn. 

Ellexberger  uiid  Hofmeis^ter.  Archiv.  f.  wissensch.  u.  j^rakt.  Thierliellk. 
Bd.  XI,  S.  162. 

—  Hesse.     Deutsche  Med.   Wochenschr.     1885.     Xu.  24. 

Galippe  et  YiGXAL.  Xote  sur  les  microorganisms  de  la  carie  dentaire. 
[L'Odo/itoIoffie.     Mars,  1889.) 

—  Magitot.     Traite  de  la  carie  dentaire.     1867.     P.  60. 

—  Mummery.  Trans,  of  the  Odont.  Soc.  of  (?r.  Britain.  Xew  Series.  1870. 
Vol.  II.     P.  7. 

W.  C.  Barrett.  An  Examination  of  the  Condition  of  the  Teeth  of  Certain 
Prehistoric  Kaces.      [Indcp.  Pract      October,  188:^.) 

—  Miller.     Prehistoric  Teeth.     {Ibid.     1884.     P.  40.) 

R.  Koch.  Ueber  Desinfection.  [Mittheilungen  aus  dem  Kaisej-l.  Gesundheits- 
amt.     Bd.  I,  S.  234  ) 

—  Black.     Antiseptics.     {Dental  Review.     1889.     Xos.  2  and  3.) 

—  Miller.     Indep   Pract.     June,  1884. 

—  Tassixari.  Centralhlatt  fiir  Bacteriologie  und  Parasitenkunde.  1888.  Bd. 
IV,   S.  449. 

—  Hvxter.     a  Treatise  on  the  Venereal  Disease.     1786.     P.  391. 

—  Lettsom.     Transactions  of  the  Medical  Society  of  London.     Aus;-.  2,  1 786 . 

—  Stricker.     Die  Bedeutung  des  Mundspeichels.     1889.     S.  138. 

—  Eberle.     Die  Verdammg.     1834.     S.  34. 

—  Senator.     Tint ei-suchungen  iiber  d.  fieberhaften  Process.     1873.     S.  6. 

—  Raynaud  et  Lastneloxgue.  Bulletin  de  VAcademie  de  med.  18  .Janvier. 
1881. 

L.  PA.STEUR.     Ihid.     18  et  25  Janvier.  1881. 

—  VuLPiAX.     Ihid.     29  Mars,  1881. 

—  Sternberg.     Bulletin  of  the  Xational  Board  of  Health.     April  30,  !S81. 

—  Griffin.     Archivio  j^er  le  scienze  mediche.     Vol.  V.     Ease.  3. 

Gaglio  et  Di  Mattel  Sulla  non  essistenza  di  una  proprieta  tossica  della  saliva 
umana.  {Arch,  j^er  le  .scienze  jned.  1882.  Vol.  VI,  Ease.  1.  Eeferat im  C'e?;yra/W. 
f.  klin.  Med.     1883.     S.  261.) 

A.  Eraxkel.     Verhandl.  d.  3.  Congr.  f.  innere  Med.     1884. 

—  Miller.     Deutsche  Med.  Wochenschr.     1884.     No.  25. 

—  Kleix".  Ein  Beitrag  zur  Kenntniss  der  Pneumokokken.  {Centralhl.  f 
med.  Wissensch.     1884.     No.  30.     S    529.) 

—  Kreibohm.     Elvigge,  Mikroorganismen.     S.  257. 

A.  Eraxkel.     Zeitsehr.f.  klin.  Med.     1886.     Bd.  X.     S.  401. 

—  Batjmgartex.     Lehrbuch  d.  pathol.  Mykologie.     1888.     S.  245. 

—  Koch.     Mitth.  a.  d.  Kais.  Gesundheitsamt.     Bd.  II.     S.  42. 

—  Gaffky.     v.  Langenbeck's  Archiv.     Bd.  XXVIII,  Heft  3.     S.  500. 

—  BioxDi.     Breslauer  arztliche  Zeitschr.     September,  1887.     Xo.  18. 

—  Zakharevitsch.     Vrach  Xo.  34.     S.  523. 

—  V.  MosETiG-MoORHOF.  Oesttrr .-Ung .  Vierteljahrsschr.  f.  Zahnheilkunde. 
1885.     Heft  2. 

—  Zawadzki.  Gaz.  lekarska.  1886.  Xo.  8.  Erom  the  Deutsche  Med 
Wochenschr. 


652  LITERATURE. 

—  Pakeeidt.  Zur  Antiseptik  beim  Zahnaiisziehen.  [Deutsche  MonafsfcJn-.  f. 
Zahnhellk.     1888.     Heft  7.     S.  254.) 

—  Bu.scH.     Deutsche  Med.  Wochenschr.     1885.     No.  24. 

—  PoRKE.     Dental  Record.     October,  1887. 

—  Baker.     Ibid.     July,  1888. 

—  PoNCET.     Gaz.  des  Hopit.     No.  19. 

—  Fripp.     Dental  Record.     August,  1887. 

—  CooPMAX.      Correspondenzhl.  f.  Zahnarzte.     Januar,  1888.     S.  56. 

—  Pietrzikowski.  Oester.-Ung  Viertel'iahrsschr.  fur  Zahnheilk.  1886.  S 
363 

—  SCHMID.      Oesterr.-Uuff.  Vierieljahrsschr.  f.  ZaJmhcilk.      1885.     Heft  I. 

—  Eitter.      Coi^respondenzhl.  f.  Zahnarzte.     October,  1888. 

—  Odexthal.  Cariose  Zaline  als  Eingangspforte  infectiosen  Materials  und 
Ursache  chronischer  Lymphdrusenscliwellungen  am  Halse.  (Inaugural  Disserta- 
tion.    Bonn,  1887  ) 

—  UjStgar.  Sitzung  der  Niederrbein.  Gesellscliaft  fiir  Xatur-  und  Heilkundt- 
7.U  Bonn,  1884.     Mai  17. 

—  Jaefe.  Lungengrangran,  durcli  einen  verscbluckten  Kirscbkern  erzeugt. 
[Allgem  med.  Zeitung.     1886.     S.  233.) 

Letden  und  Jaffe.  Ueber  putride  (fcetide)  Sputa.  [Deuisches  Archiv.  f. 
kiln.  Med      1867.     Bd.  II.     S.  488.) 

—  Baumgartex.     Jahresbericbt.      1  Jabrgang.     S.  142. 

—  Baginsky.     Deatsehe  Med.   Wochenschr.     1888.     ISTo.  20. 

—  Bednar.     Krankbeiten  der  ISTeugeborenen  und  Sauglinge.     1854.     S.  54. 

—  Henoch.  Klinik  der  Unterleibskrankbeiten,  S.  589  und  Beitrage  zur 
Kinderbeillvunde.     Bd.  I,  S.  Ill,  und  Bd   II,  S.  309. 

—  Natjntn.  Ueber  das  Verbaltniss  der  Magengabrungeu  zur  mecbaniscben 
Magen-Insufficienz.     [Archiv  f.  klin.  Med.     Bd.  XXXI,  S.  225.) 

—  Leube.     Archiv  f.  klin.  Med.     Bd.  XXXIII,  S.  4. 

—  De  Barx.  Zur  Kenntniss  der  niederen  Organismen  im  Mageninbalte. 
[Archiv  f.  exper.  Pathol,  u.  Pharmakol.     1886.     Bd.  XX,  S.  243.) 

—  Frerichs.  Wagner's  Handworterbucb  der  Pbysiol.  Bd.  III.  1  Abtb 
S.  869. 

—  EwALD.     Die  Lehre  von  der  Yerdauung.     1886.     S.  104. 

—  EscHERiCH.  Beitrage  zur  antiseptiscben  Bebandlungsmetbode  der  Magen- 
Darmerkrankungen  des  Siiuglings.  [Therap.  Monatshefte  1887.  S  390)  und 
Die  desinficirende  Bebandlungsmetbode  der  Magen-Darmkrankbeiten  des  Saug- 
lingsalters      [Centralbl.  f.  Bacteriol.  u.  Parasitenkunde.     1887.     Bd.   II,  ISTo.  21). 

—  Minkowski.     Ueber  die  Gabrungen  im  Magen.     1838. 

—  Miller.     Deutsche  Med.  Wochenschrift.     1885.     jSTo   49. 

—  MacFadyan.     Fliigge.     Milcroorganismen.     1885.     S.  590. 

—  SucKSDORF.  Das  quantitative  Yorkommen  von  Spaltpilzon  im  menscb- 
licben  Darmcanal.     [Archiv.f.  Hygiene.     1886.     Bd.  lY.) 

—  Baumgartek.     Ccntralbl.  f.  klin.  Med.     1884,  No.  2. 

—  Miller.     Deutsche  Med.  Wochenschr.     1885,  No.  49.     1886,  No.  6. 

—  Koch.  Zweite  Serie  zur  ;?ur  Erorterung  der  Cbolerafrage.  [Deutsche  Med. 
Wochenschr.     1885.     No.  19,  etc.) 

Bland  Sutton.     Deutsche  Med.  Wochensclir.     May,  1887. 

—  Eeeve.     Indep.  Pract.     Yol.  YI,  P.  367 

—  Bennett.     Dental  Record.     May,  1887.     Pp.  229,  233. 

—  ScHECH.     Krankbeiten  der  Mundbdble,  des  Kaebens  und  der  Nase. 


LITERATURE.  653 

—  LoFFLER.     Mitth.  a.  d   Kais.  Gesandheltsamt.     Bd.  II,  S.  480. 

—  DrLLES.     Medical  and  Surgical  Reporter.     January,  1878. 

—  Otis.     Lectures  on  Syphilis.     New  York,  1887.     P.  102. 

—  Lanceraux.      Proceedings   Academie   de   Medicine   de   Paris.      (Z/'  Vidon 
Medieale.     1889.     P.  655.) 

—  Giovanni.     Lo  Sperinientale.     1889.     P.  262. 

—  Lenoir.     Legons  sur  la  Syphilis.     1886.     P.  62. 

—  Ltdston.     Jowr.  of  the  Am.  Med.  Ass.     1886.     P.  654. 

—  EoDDicK.     Montreal  Med.  Jour.     Augast,  1888.     P.  93. 
— :  Parker.      Western  Dent.  Jour,     February,  1890. 

—  Bollinger.     Centralhl  f.  d.  Med.   Wissench.     1877.     jSTo.  27. 

—  Bo^^TRO>I.     Verh.  d.  Congr.  f  innere  Med.     Wiesbaden,  1885.     S.  94. 

—  PoNFiC'K.     Ueber  eiue  wahrscheinlich  mykotische  Form  von  Wirbelcarie.s. 
[Berliner  Min.   Wochenschr.     1879.     S.  345.) 

James  Israel.     Klinische  Beitrage  zur  Aktinomykose  des  Menscheii.     1885. 

—  HocHENEGG.     Zur   Casuistik  der  Aktinomykose   des   Menschen.     ( Wiener 
Med.  Presse.     1887.     No.  16-18.) 

—  EoTTER.     Demonstration   von   Impfaktinoniykose.     {Tagebl.  der  Naturfvr- 
scher-Versammlung.     Wiesbaden,  1887.     S.  272.) 

—  Partsch.     Einige  neue  Fiille  von  Aktinomykose  des  Menschen.     {Deutsche 
Zeitschr.f.  Chirurgie.     1886.     Bd.  XXIII,  S.  498.) 

—  MoosBRTJGGER.     Uebcr  die  Aktinomykose  des  Menschen.     (See  Baiimgar- 
ten's  Jahresbericht,  1886.     S.  317.) 

—  KosER.     Deutsche  Med.   Wochenschr.     1886.     No.  22.     S.  369. 

—  Braun.     Ueber  Aktinomykoise  des  Menschen. 

—  Laurent.     Handbuch  der  ges.  Medicin.     S.  263. 

—  Plaut.     Neue  Beitrage  zur  systema'tischen  Stellung  des  Soorpilzes  in  der 
Botanik.     Leipzig,  1887. 

—  Klemperer      Leber  die  Natur  des  Soorpilzes.     [Centralhlatt  fur  klin.  Med. 
1885.     No.  50.     S.  849.) 

—  Baginsky.    Ueber  Soorculturen.    [Deutsche  Med.  Wochenschr.    1885.    No. 
50.     S   866.) 

P.  Gratvitz.     Ueber  die  Para.siten  des  Soors,  etc.     {Virchow's  Archiv.     1886. 
Bd.  CIII,  S.  393.) 

—  Frankel.     Grundriss  der  Bacterienkunde. 

—  ZoPF.     Pilzthiere  oder  Schleimpilze.     1885. 

—  De  Bary.     Moiphologie  uud  Biologie  der  Pilze.     1884.     S.  453. 

—  WoRONiN.     Priugsheim's  .Jahrbiicher  fiir  Wissensch.  Botanik.    1878.    Bd. 
XL 

E.  Koch.     Mitth.  aus  d.  Kais.  Gesundheitsant.     1881.     Bd.  I. 

—  EiDAM.     Allg.  landwirthschaft.  Zeitung.     1880.     No.  97. 

CHAP  TEE    XL  I. 

C.  Weigert.     Deutsche  Med.  Wochenschr.     1893. 

A.  W.  Harlan.     The  Ditfusibility  of  Medicaments  in  Living  and  Dead  Den- 
tine.    [Dental  Review.     1891.) 

W.  E.  Ide.     The   Use   of  Arsenious   Acid,   etc.     [Am.  Jour,  of  Dent.   Sci. 
1842.) 

.     Arsenic  as  a  Dental  Therapeutic  Agent,     [Am.  Jour.of  Dent.  Sci. 

1845.) 

45 


654  LITERATURE. 

A.  Westcott.     Ai-senic  as  a  Kemedy,  etc.     {Am.  Jour,  of  Dent.  Sci.     1845.) 
A.  C.  Castle.     The  Use  and  Abuse  of  Arsenious  Acid.  etc.     {Am.  Jour,  of 
Dent.  Sci.     1850.) 

.     Application  of  Arsenic  to  Teeth.     {Am.  Jour,  of  Dent.  Sci.     1859.) 

L.  A.  Fatjght.     a  Study  of  Arsenious  Acid.     {Indep.  Pract.     1889.) 
J.  Tkumajj.     The  Pulp  and  Treatment  of  Pulp-Canals.     {Intern.  Dent.  Jour. 
1889.) 

C.  Bixz  and  H.  Schtjlz.     The  Action  of   Ai-senic.     {Missouri  Dent.   .Jour. 
1879.) 

GiES.     Physiological  Etfect  of  Ai-senic.     {Missouri  Dent.  Jour.     1879.) 

C.  BzNZ  and  H.  Schulz.     Chemical  Cause  of  the  Poisonousness  of  Arsenic. 
{Missouri  Dent.  Jour.     1881.) 

F.  Wakdropes.     Arsenical  Poisoning.     {Missouri  Dent.  Jour.     1882.) 

.     Arsenical  Application.     {New  Eng.  Jour,  of  Dent.     1882.) 

Ai-senic,  etc.     {Archives  of  Dent.     1886.     P.  -331.) 

J.    G.    Harper.      Dental    Medicine   and    Therapeutics.     {Archives   of   Dent. 
1889.) 

H.  G.  Crowell.     Arsenic.     {Archives  of  Dent.     1891.) 

H.  H.  SiLLiMAX.     Pain  Folio -w'ing  Arsenic  Application.     {Archives  of  Dent. 
1891.) 

J.  "W.  Ellis.     Ai'senic.     {Dental  Costnos.     Vol.  III.) 
H.  Meredith.     Arsenic.     {Dental  Cosmos.     Yol.  III.) 
C.  B.  Foster.     Arsenic.     {Dental    Costnos.     Vol.  III.) 
H.  M.  "White.     Arsenic.     {Dental  Cosmos.     Yol.  III.) 
W.  H.  Atkixsox.     Arsenical  Treatment,  etc.     {Dental  Cosmos.     Yol.  III.) 
J.  H.  McQuillex.     Experimental  Observations  on  the  Action  of  Arsenic,  etc. 
{Dental  Cosmos.     Yol.  III.) 
A.  C.  Hawes.     Use  of  Arsenic,  etc.     {Dental   Cosmos.     Yol.  Y.) 
Editorial.     Sensitive  Dentine — Arsenic,  etc.     {Dental  Cosmos.     Yol.  Y.) 
"W.    H.   Atkinson.     Treatment    of    Sensitive    Dentine.         {Dental    Cos??ws. 
Yol.  Y.) 

W.  Dickinson.     Cobalt,  etc.     {Dental  Cosmos.     Yol.  YII.) 
J.  F.  Flagg.     Arsenious  Acid,  etc.     {Dental  Cosmos.     Yol.  X.) 
J.  H.  McQuiLLEN.     Arsenical  Applications.     {Dental  Cosmos.     Yol.  XIII.) 
C.  F.  W.  BQdecker.     On  the  Action  of  Arsenious  Acid  upon  Dentinal  and 
Pulp-Tissue.     {Dental  Cosmos.     Yol.  XXY.) 

L.  A.  FArGHT.     Arsenious  Acid.     {Dental  Cosmos.     Yol.  XXXI.) 
C.  F.  W.  BOdecker.     The  Herbst  Method  of  Treating  Pulps.     {Dental  Cosmos. 
Yol.  XXXIY.) 

A.  "W.  Harlan.  The  Herbst  Method  of  Treating  Pulps.  {Dental  Costnos. 
Yol.  XXXY.) 

W.  E.  Christensen.  Some  Comments  upon  the  Herbst  Method  of  Treating 
Pulps.     {Dental  Cosmos.     Yol.  XXXY.) 

J.  F.  Flagg.  Arsenious  Acid  as  a  Devitalizer  of  the  Dental  Pulp.  (Trans. 
Amer.  Dent.  Association.     1862.) 

F.  A.  Brewer.  The  Tendency  of  Arsenic  as  Applied  to  Dental  Tissue  to 
Develop  Pericementitis,  and  Its  Sequence — Alveolar  Abscess.  (Trans.  California 
State  Dental  Association.     1882.) 

HOHL.     Beitrag  zur  Arsenik  Frage.     {Deut.    Vier.  Jahrsch.  f.  Zahnheilk. 

1868.) 
Flugge.     Die  Mikroorganismen.     S.  110. 


LITERATURE.  655 

H.  HuMM.     tjber  Arsenpasta.     {Deut.  Vier.  Jahrsch.  f.  Zahnheilk.     1875.) 
C.  KuHNs.     Arsenicum  nativum.      i^Deut.   Vier.  Jahrsch.  f.  Zahnheilk.     1876.) 
A.  F.  Schmidt.     Xochmals  Ai-seu.     {Deut.  Monatssehr.  f.  Zahnheilk.     1884.) 
—  ScHXEiDER.     Die  Auwendung-  des  Arsens  in  der  Zahniirztlichen  Praxis. 
(^Deui.  Viert.J.  Zahnheilk.     1880.) 

J.  Arkovy.     Bei'ichte  iiber  einige  Experimente  beziiglich  der  Devitalisation 
der  Pulpa.     {Dent.  Monatssehr.  f.  Zahnheilk.     1882.) 

J.  E.  Dexter.     Arsenic.     (Trans.  First  Dist.  Dent  Soc.  IST.  Y.     1883.) 
S.  Baxter.     Kalium  arsenicosum  ein  neues  Dentine  Anaestheticum.     [Odonto- 
skop.     1893.) 

T.  Steyexsox.     On  the  Behavior  of  Arsenic  in  Contact  with  Putrefying  Or- 
ganic Substances.     [Brit.  Jour,  of  Dent.  Sci.     1883.) 

W.  K.  Tuck.     Arsenical  Poisoning.     {Brit.  Jour,  of  Dent.  Sci.     1891.) 

CHAPTEE    XLII. 

T.  L.  Gilmer.     Necrosis  of  >[axillaiy  Bones.     {Denial  Review.     1891.) 

G.  H.  McC au.se Y.     Xecrosis.     {Dental  Review.     1890.) 

T.   "W.   Brophy.      Caries  and    Xecrosis   of   the    Maxillary   Bones.     {Dental 

Review.     1888.) 

J.  D.  White.     Caries  and  Xecrosis  of  Bone.    {Dental  News  Letter.     1856  and 

1867.) 

M.  Depaul.     Xecrosis  of  the  Lower  Jaw.     {Am.  Jour,  of  Dent.  Sci.     1845.) 
M.  MoxoD.     Xecrosis  from  Pressure  of  the  Dens  Sapientiaj.     {Am.  Jour,  of 

Dent.  Sci.     1845.) 

Dr.  Heifelder.    Xecrosis  of  the  .Jaw-Bones.     {Ain.  Jour,  of  De/it.' Sci.     1845.) 
A.  A.  Blaxdy.     Inflammation  of  the  Gums  and  Exfoliation  of  the  Alveolar 

Process.     {Am.  Jour,  of  Dent.  Sci.     1849.) 

W.  Jones.     A  Case  of  Reproduction  of  the  Inferior  Maxillary  Bone.     {Am. 

Jour,  of  Dent.  Sci.     1852  and  1853.) 

— '■  .      Xecrosis  of   the  Superior  and  Inferior  Maxilhw      {Am.  Jour,  of 

Dent.  Sci.     1852.) 

W.  A.  Shelby.     Caries  and  Exfoliation  of  the  Jaw.     {Am.  Jour,  of  Dent.  Sci. 

1858.) 

W.  G.  Smull.     Xecrosis  of  the  Lower  Jaw.     {Am.  Jour,  of  Dent.  Sci.     1854.) 
J.  R.  Wood.     Xecrosis  of  the  Inferior  Maxillary  from  the  Vapor  of   Phos- 
phorus.    Removal  of  the  Entire  Lower  .law,  etc.    {Am.  Jour,  of  Dent.  Sci.    1856.) 
J.  Richardson.     Gangrenous  Degeneration  of  the  Cheek  and   Gums,    with 

Xecrosis,  etc.     {Am.  Jour,  of  Dent,  Sci.     1857.) 

J.  H.  Martindale.     Caries  and  Xecrosis  of  the  .laws.     {Indep.  Practitioner. 

1886.) 
H.S.Chase.     Xecrosis.     {Missouri  Dent.  Jour.     1875.) 
J.  D.  Pearsox.     Xecrosis.     {Missouri  Dent.  Jour.     1876.) 
R.  G.  Peaksox.     Xecrosis.     {Missouri  Dent.  Jour.     1877.) 
G.  A.  Christmax.     Xecrosis.     {Missouri  Dent.  Jour.     1879.) 
W.  H.  Atkixsox.     Xecrosis.     {Missouri  Dent.  Jour.     1881.) 
H.  O.  Camerox'.     Phosphorus  Xecrosis.     {Missouri  Dent.  Jour.     1882.) 
Dr.  Cripps.     Cancrum  Oris  leading  to  Xecrosis  of  Lower  Jaw.     {Archives  of 

Dent.     1884.) 
J.  P.  McCarthy.     Xecrosis  of  the  Maxillary  Bones  after  Measles.     {Archives 

of  Dent.     1891.) 


656  LITERATURE. 

J.  McCalla.  Spontaneous  Necrosis  of  the  Alveolar  Process.  [Drntnl  Cosmos. 
Vol.  I.) 

—  .     On  the  Osteogenic  Properties  of  the  Periosteum.     (^Drntnl  Cosmos. 

Vol.  I.) 

M.  Grandidier.     Necrosis  of  the  Upper  Jaw,  etc.     [Denial  Costnos.     Vol. 
III.) 
Prof.  Billroth.     Phosphor  Necrasis.     {Denial  Cosmos.     Vol.  III. ) 

—  Lawson.     Necrosis  of  Lower  Jaw.     [Dental  Cosmos.     Vol.  IV.) 

H.  Jackson.     Exfoliation  of  One  of  the  Pre-Maxillary  Bones  after  Measles 
{Denial  Cosmos.     Vol.  IV.) 
W.  S.  Savory.     Caries  and  its  Eelation  to  Necrosis.     {Denial  Cosmos.     Vol. 

V.) 

T.  Bryant.     Exfoliation  of  the  Intermaxillary  Bones  of  an  Adult.     {Denial 

Cosmos.     Vol.  VI.) 

C.  P.  Fitch.  Necrosis  of  the  Teeth.  {Denial  Cosmos.  Vol.  VI.) 
N.  E.  Smith.  Necrosis  of  Jaw,  etc.  {Denial  Cosmos.  Vol.  VII.) 
W.  H.  Atkinson.     Necrosis,  etc.     {Dental  Cosmos.     Vol.  VIII.) 

—  Paget.     Necrosis  of  the  Lower  Jaw.     (Denial  Cosmos.     Vol.  VIII.) 
Prop.  Gross.     Necrosis  of  Lower  Jaw.     {Dental  Cosmos.     Vol.  X.) 

T.  G.  Lewis.     Necrosis.     {Denial  Cosmos.     Vol.  XL) 
C.  Heath.     Necrosis,  etc.     {Dental  Cosmos.     Vol.  XII.) 

C.  Fryer.  Caries  of  Hard  Palate  from  Syphilis.  {Denial  Cosm.os.  Vol. 
XII.) 

J.  H.  McQctllen.     Necrosis,  etc.     {Dental  Cosmos.     Vol.  XII.) 
E.  H.  Preston.     Caries  and  Subsequent  Eemoval  of  the  Whole  Inferior  Max- 
illa.    {Denial  Cosmos.     Vol.  XIII.) 

J.  S.  Bailey.  Necrosis  of  the  Inferior  Maxilla.  {Denial  Cosmos.  Vol. 
XIII.) 

W.  Fergusson.     Necrosis  of  Lower  Jaw.     {Denial  Cosmos.     Vol.  XIII.) 

T.Bryant.     Necrosis  of  Lower  Jaw.     {Dental  Cosmos.     Vol.  XIII.) 

S.  J.  Cobb.     Necrosis  of  Upper  Jaw.     {Dental  Cosmos.     Vol.  XIII.) 

A.  Eobertson.     Necrosis,  etc.     {Denial  Cosmos.     Vol   XIV.) 

E.  E.  Pettit.     Caries  of  Maxillary  Bones,  etc.    {Dental  Cosmos.    Vol.  XIV.) 

—  Sayre.     Necrosis  of  Jaw.     {Dental  Cosmos.     Vol.  XIV.) 

E.  VAN  DE  Warker.     Necrcsis,  etc.     {Dental  Cosmos.     Vol.  XIV.) 
W.  Tay.     Necrosis  of  Lower  Jaw.     {Dental  Cosmos.     Vol.  XVI. ) 
,J.  Hutchinson.     Syphilitic  Necrosis,  etc.     {Dental  Cosmos.     Vol.  XVI.) 
W.  S.  Savory.     Necrosis  from  Phosphorus.     {Dental  Cosjnos.     Vol.  XVI.) 

■.     Phosphorus  Necro.sis.     {Dental  Cosmos.     Vol.  XVI.) 

.      Pho.sphorus    Necrosis    of    Upper   Jaw.     {Denial    Cosmos.      Vol. 

XVII.) 

W.H.Atkinson.     Necrosis  and  Caries.     {Dental  Cosi7ios.     Vol.  XVIII.) 
.     Necrosis  and  Fistula.     {Dental  Cosmos.     Vol.  XIX.) 

—  . .     Necrosis  of  the  Lower  Jaw.     {Dental  Cosmos.     Vol.  XIX.) 

.     Necrosis  following  Smallpox.     {Dental  Cosmos.     Vol.  XX.) 

. .     Dental  Abscesses  and  Fistula.     {Dental  Cosmos.     Vol.  XX.) 

C.  F.  W.  BOdecker.     Necrosis.     {Dental  Cosmos.     VoJ.  XX.) 

J.  E.  Mears.  Necrosis  of  Superior  Maxillary  Bone  following  Typhoid  Fever. 
{Denial  Cosmos.     Vol.  XXII.) 

.  Fistulous  Opening  in  the  Shoulder  from  a  Carious  Tooth.     {Denial 

Cosmos.     Vol.  XXII.) 


LITERATURE.  657 

G.   Bruhxs.     Phosphorus   Necrosis   of    the   Facial    Bones.     [Denial    Casinos. 

Vol.  XXIII.) 

■.     Necrosis  of  the  Maxilhe.     [Dental  Cosmos.     Vol.  XXIII.) 

.     Six  Cases  of  Syphilitic  Xecrosis  of  the  Jaw.     [Dental  Cosmos. 

Vol.  XXIV.) 

—  Post.     Necrosis  of  Jaw,  etc.     [Dental  Cosmos.     Vol   XXV  ) 

A.  MoxEY.  Necrosis  of  Upper  Jaw  in  Typhoid  Fever.  [Dental  Cosmos. 
Vol.  XXVI.) 

J.  E.  Mears.     Phosphorus  Necrosis.     [Dental  Cosmos.     Vol.  XXVII.) 

—  Hutchinson.  Necrosis  of  Jaw  from  Administration  of  Phosphorus.  [Den- 
tal Cosmos.     Vol.  XXIX.) 

J.  H.  Maktindale.     Caries  and  Necrosis.     [Dental  Cosmos.     Vol.  XXXI.) 

G.  F.  Lydstox.  The  Kelation  of  Tropho-Neurosis  to  Diseases  of  the  Mouth 
and  .laAvs,  with  Special  Eeference  to  Syphilitic  Necrosis.  [Dental  Cosmos.  Vol. 
XXXII.) 

D.  M.  Sabater.  Necrosis  :  Its  Microscopical  Appearance,  etc.  [Dental  Cosmos. 
Vol.  XXXIII.) 

L.  L.  Dunbar.  Caries  and  KecuiTetit  Caries  of  the  Inferior  Maxillary  Bone. 
(California  State  Odont.  Society.     1884.) 

W.  H.  Atkinson.     Necrosis.     (Trans.  Dent.  Soc.  of  the  State  of  N.  T.     1877.) 

—  Balfoue.  tJber  die  Wirkung  der  Phosphordjirapfe  auf  die  Zahne,  etc. 
(Z>er  Zahnarzt.     1847.) 

—  JtJNGKEN.  tJber  den  Knochenbrand  der  Kiefer  bei  den  Arbeitern  in  den 
Phosphorziindholz  Fabriken.     [Der  Zahnarzt.     1848.) 

—  Helft.  Zur  Pathologic  des  Kieferleidens  der  Arbeiter  in  den  Pho.'^pbor- 
ziindholz  Fabriken.     [Der  Zahnarzt.     1848.) 

J.  Eoc'yer.     Necrose  der  Kieferknoehen.     [Der  Zahnarzt.     1856.) 
H.  Santesson.     tJber  Phosphornekrose.     [Der  Zahnarzt.     1857.) 

—  HuBE.  tJber  einen  eigenthiimlichen  Fall  ausgedehnter  syphilitischer  Zer- 
storung  des  oberen  Alveolarfortsatzes,  etc.     [Verh.  d.  Deut.  Odont.  Ges.     Bd.  II.) 

Fr.  Kleinmann.  tJber  Phosphor-Necrosen,  etc.  [Deut.  Vier.  Jahrsch.  f. 
Zahnheilk.     1882.) 

—  Kitter.  Ein  Fall  von  Unterkiefernekrose  mit  todtlichem  Ausgange 
[Deut.  3Ionatssch.  f.  Zahnheilk.     1886.) 

—  Salzer.  Ein  Fall  von  Nekrose  der  Alveole  nach  Gangraen  der  Pulpa 
[Odontosktjp.     1892.) 

W.  R.  Graves.  A  Case  of  Tubercular  Caries  of  Palatine  Plates  of  Superior 
Maxillary  Bones,  etc.     [Monthly  Revleiv  of  Detit.  Surg.     1891.) 


CHxVPTEE    XLIII. 

H.  C.  QuiNBY'.  Interesting  Case  of  Ulceration  of  the  Lining  Membrane  of 
the  Maxillary  Sinus.     [Dental  Cosmos.     Vol.  V.) 

— ■  Schwartz.  Empyem  der  Highniorshohle.  [Breslauer  arztliehe  Zeitseh. 
1889.) 

A.  NoRDMANN.     Uber  das  Empyem  der  Oberkieferhdhle.     (Strassburg,  1890.) 

W.  C.  Starbxtck.  Mucous  Engorgement  of  the  Maxillaiy  Sinus.  [John- 
ston's  Dental  Miscellany.     1875.) 

D.  H.  GooDWiLLiE.  Case  of  Suppurative  Disease  of  the  Antrum.  [John.ston's 
Dental  Miscellany.     1880.) 


658  '  LITERATURE. 

I.  B.  Davenport.     A  Case  of  Antral  Disease  treated  through  a  Lateral  In- 
cisor.    {Johnston's  Dental  Miscellany.     1881.) 

E.  Mawhinnet.     Diseases  of  the  Antrum.     [Dental  Review.     1893) 
I.  P.  Wilson.     Abscess  of  the  Antrum,  etc.     [Dental  Review,     1892.) 

F.  H.  BoswoRTH.     Various  Forms  of  Diseases  of  the  Ethmoid  Cells.     [New 
York  Med.  Jour.     1892.) 

G.  L.  MoRGEXTHAN.     Kecent  Contributions  to  the  Diagnosis  and  Treatment 
of  Empyema  of  the  Maxillar}'  Sinus.     [Dental  Review.     1882.) 

I.  P.  Wilson.     Pathological  Conditions  of  the  Ethmoid  Bone  Resulting  from 

Dental  Lesions.     [Dental  Revieio.     1890.) 

S.  P.  HuLLiHEN.     Observations  on  the  Antrum    Maxillare.      [Am.  Jour,  of 

Dent.  Sci.     1842.) 

W.  W.  H.  Thackston.     Diseases  of  the  Maxillary  Sinuses.     [Am.  Jour,  of 

Dent.  Sci.     1842.) 

C.  A.  Harris.     Diseases  of  the  Antrum.     [Am.  Jour,  of  Dent.  Sci.     1843.) 
C.  A.  Harris.     Fungous  Tumor  of  the  Antrum.     [Am.  Jour,  of  Dent.  Sci. 

1845.) 
E.  J.  Dillingham.    Abscess  of  the  Antrum.    [Am.  Jour,  of  Dent.  Sci.    1846.) 
W.  H.  DwiNELLE.     Perforation  of   the  Antrum.     [Atyi.  Jour,  of  Dent.  Sci. 

1848.) 

J.  Weathekby.     Abscess  of  the  Antrum.     [A?7i.  Jour,  of  Dent.  Sci.     1848.) 
W.  Fergusson.     Disease  of  the  Antrum.     [Am.  Jour,  of  Dent.  Sci.     1860.) 
H.  Dubs.     Diseased  Antrum,  etc.     [Am.  Jour,  of  Dent.  Sci.     1850.) 
R.  D.  Addington.     Operation    on    the   Antrum.     [A77i.   Jour,   of  Dent.  Sci. 

1850.) 

R.  D.  Cough.     Disease  of  the  Antrum.     [A/n.  Jour,  of  Dent.  Sci.     1850.) 
W.  Cooper.     Spontaneous  Collapse  of  the  Walls  of  the  Antrum.     [Am.  Jour. 

of  Dent.  Sci.     1850.) 

M.  ViGUERiE.     Cancerous   Tumor  within  the  Antrum.     [Am..  Jour,  of  Dent. 

Sci.     1850.) 

Mr.  Levison.     Disease  of  the  Antrum,  etc.     [Am..  Jour,  of  Dent.  Sci.    1852.) 
J.  A.  GiRALDES.     Diseases  of  the  Maxillary  Sinus.     [Am.  Jour,  of  Dent.  Sci. 

1856.) 
P.  M.  Fay.     Dropsy  of  the  Antrum.     [Penn.  Jour,  of  Dent.  Sci.     1875.) 
J.  N.  Farrar.     Diseases  of  the  Antrum,  etc.     [Intern.  Dent.  Jour.     1889.) 
H.  S.  Chase.     Tumor  upon  the  Antrum.     [Missouri  Dent.  Jour.     1869.) 
H.  S.  Chase.     Polycystic    Tumor   of    the   Antrum.     [Missouri   Dent.    Jour. 

1870.) 
H.  S.  Chase.     Inflammation  of  the  Antrum.     [Missouri  Dent.  Jour.     1870.) 
T.  W.  Reed.     Diseased  Antrum.     [Missouri  Dent.  Jour.     1876.) 
H.   Fox.     Pus  in  the  Antrum.     [Missouri  Dent.  Jour.     1876.) 
L.  Browne.     Abscess  of  the  Antrum.     [Missouri  Dent.  Jour.     1880.) 
H.  Evans.     Abscess  of  the  Antrum.     [Missouri  Dent.  Jour.     1881.) 
—  .     Abscess  of   the    Antrum    not   Caused  by  any  Disease  of  Teeth. 

[Missouri  Dent.  Jour.     1881.     P.  509.) 

A.  J.  Prager.    Suppuration  in  the  Antrum,  etc.    [Missouri  Dent.  Jour.    1882.) 
A.    W.  Harlan.      The   Antrum    Highmorianiun.       [Archives   of  Dentistry. 

1885.) 

M.  J.   Davis.     Antrum  Disease,  etc.     [Archives  of  Dentistry.     1886.) 

J.   W.  Plummer.     Abscessed  Antrum,  etc.     [Archives  of  Dentistry.     1889.) 

J.  Green.     Dropsy  of  the  Antrum.     [Dental  Cosmos.     Vol.  I.) 


LITERATUKE.  659 

"VY.  Fergussox.     Disease  of  the  Antrum.     [Dental  Cosmos.     Vol.  I.) 

H.  M.  White.     Abscess  of  the  Antrum.     [Dental  Cosmos.     Yol.  II.) 

H.  A.  Beamer.     Dropsy  of  the  Antrum.      [Dental  Cosmos.     Yol.  II.) 

H    M.  White.     Dropsy  of  the  Dental  Sac.     [Dental  Cosmos.     Yol.  Y.) 

T.   Bryant.     Cyst  of  the  Antrum      [Dental  Cosmos.     Yol.  YI.) 

W.  T.  Bullock.    Cystic  Tumor  of  the  Antrum.     [Dental  Cosmos.    Yol.  YII.) 

H.  S.  Chase.    Encysted  Tumor  of  the  Antrum.    [Dental  Cosmos.    Yol.  YIII.) 

—  MiCHELSOiSr.  Zur  Diagnose  unci  Therapie  des  Empyems  der  Highmoi-s- 
hohle.     [Berliner  Klin.  Wochenschr.     1889.) 

0.  Chiari.  tjher  Empyema  Antri  Highmori.  ( Wloier  Klin.  Wochenschr. 
1889.) 

—  Hartmaxn.  tJber  Empyemder  Oberkieferhohle.  [Deut.  Med.  Wochenschr. 
1889.) 

G.  S.  FouKE.     Polypus  of  the  Antrum.     [Dental  Cosmos.     Yol.  YIII.) 
H.  Smith.     Disease  of  the  Antrum.     [Dental  Cosmos.     Yol.  IX. ) 

—  Derby.     Dropsy  of  the  Anti-um.     [Dental  Cosmos.     Yol.  X.) 

C.  H.  Moore.  Antrum  of  Highmore,  Expansion  Thereof  [Dental  Cosmos. 
Yol.  XII.) 

C.  E.  Latimer.     Diseases  of  the  Maxillary  Sinus.    [Dental  Cosmos.  Yol.  XII. ) 
L.  F.  Hartey.     The  Antrum  of  Highmore  and  its  Diseases.     [Dental  Cosmos. 

Yol.  XIY.) 

Prof.  Armsby.  Diseases  of  the  3Iaxillary  Antrum.  [Dental  Cosmos.  Yol. 
XIY.) 

P.  Fay'.     Dropsy  of  the  Antrum.     [Dental  Cosmos.     Yol.  XYI.) 

—  Grant.     Cystic  Antral  Tumor.     [Dental  Cosmos.     Yol.  XYI.) 

.     Tumor  of  the  Antrum.     [Dental  Cosmos.     Yol.  XXII.) 

L.  Brown.     Abscess  of  the  Antrum.     [Dental  Cosmos.     Yol.  XXI.) 

L.  Howe.     Abscess  of  the  Antrum,  etc.     [Dental  Cosmos.     Yol.  XXIII.) 

E.  Owen.  On  Maxillary  Abscess  and  Necrosis  in  Childhood.  [Dental  Cosmos. 
Yol.  XXIII.) 

D.  H.  Goodwillie.  A  Tooth  Developed  in  the  Antrum.  [Dental  Cosmos. 
Yol.  XX YI.) 

D.  H.  Goodwillie.  Abscess  of  the  Antrum  of  Ten  Yeai-s'  Standing.  [Dental 
Cosmos.     Yol.  XXYI.) 

D.  H.  Goodwillie.  Tooth  Found  in  the  Antrum.  [Dental  Cos>nos.  Yol. 
XXYI.) 

D.  H.  Goodwillie.  The  Antrum  of  Highmore  and  Some  of  its  Diseases. 
[Dental  Cosmos.     Yol.  XXYI.) 

J.  S.  Marshall.  Alveolar  Abscess  Opening  into  the  Antrum  and  Nasal 
Cavity,  etc.     [Dental  Cosmos.     Yol.  XXYI.) 

F.  Warner.     Abscess  of  the  Antrum.     [Dental  Cosmos.     Yol.  XXYII.) 

—  .     Cases   of    Suppuration  in  the  Antrum.     [Dental  Cosmos.     Yol. 

XXYII.) 

M.  Smale.  Chronic  Suppuration  in  the  Antrum.  [Dental  Cosmos.  Yol. 
XXYII.) 

C.  Heath.     Diseases  of  the  Antrum.     [Dental  Cosmos.     Yol.  XXIX.) 

—  ScHlFFERS.     Catarrh  of  the  Antrum,     [Denial  Cosmos.     Yol.  XXX.) 

A.  Bronner.  Empyema  of  the  Maxillary  Sinus.  [Dental  Cosmos.  Yol. 
XXXI.) 

—  Adelmann.  Untersuch.  iiber  Krankhafte  Zustande  der  Oberkieferhohle. 
Dorpat,  1844. 


660  LITERATURE. 

A.  Schubert.  tJber  Empyem  der  Higliiiiorsliohle.  [Miinch.  Med.  Wochevschr. 
1889.) 

W.  Carr.     Disease  of  the  Antrum.     (Dental  Cosmos.     Vol.  XXXI.) 

F.  Abbott.  Disease  of  the  Antrum  Due  to  Dentsxl  Complications  and  its 
Treatment.     [Dental  Cosmos.     Vol.  XXXI.) 

I.  P.  Wilson.  Pathological  Conditions  of  the  Air  Cavities  of  the  Cranium, 
Resulting  from  Dental  Lesions.     [Dental  Cosmos.     Vol.  XXXV.) 

E.  A.  Ltjnby.  Abscessof  the  Antrum.  (Trans.  California  State  Dent.  Ass.  1886.) 

F.  Abbott.  Diseases  of  the  Antrum.  (Trans.  Dent.  Soc.  of  the  State  of 
JSr.  Y.     1883.) 

M.  Kronthal.  Schleimhautcyste  des  Antrum.  [Deut.  Monatssch.  f.  Zahn- 
hellk.     1884.) 

M.  IvROHJfTHAL.  Empyema  Sinus  MaxiUaris.  [Deut.  Monatssch.  f.  Zalmhellk. 
1884.) 

—  Schneider.  Entziinduug  des  Antrum,  etc.  [Deut.  Monatssch.  f.  Zahnheilk. 
1887.) 

C.  Eeschreiter.     Zur  Morphologic  des  Sinus  MaxiUaris.     Stuttgart,  1878. 
J.  A.  GiRALDis.     tJber  die  Schleimcysten  der  Oherkieferhohle.     [Vhrhow's 
Arch.     1866.) 

—  Eeisert.  Drei  FJille  von  Erkrankuug  des  Antri  Highmori.  [Deut.  Monats- 
schr.  /.  Zahnheilk.     1 891.) 

M.  E.  Brown.  Suppuration  of  the  Antrum  of  Highmore.  [Neiv  York  Med. 
Jour.     1891.) 

G.  ScHEFF.  tJber  das  Empyem  der  Highmorshohle  und  seinen  dentalen  Ur- 
sprung.     Wien,  1891. 

J.  I.  Hart.  Diseases  of  the  Antrum.  (Trans.  Dent.  Soc.  of  the  State  of 
N.  Y.     1890.) 

C.  Partsch.  Die  Erkrankungen  der  Kieferhohle.  In  Handb.  d.  Zahnheilk. 
von  J.  Scheff,  jr.     Wien,  1892. 

—  ZiEM.  Zur  Diagnose  und  Behandlung  der  Erkrankung  der  Kieferhohle. 
[Berliner  Klin.  Wochenschr.     1889.) 

—  Krieg.  tJber  Empyem  des  Antrum  Highmori.  [Med.  CorresjMJid.  Bl.  des 
Wiirttemb.  Arztl.  Vereins.     1888.) 

M.  Schmidt.  Zur  Diagnose  und  Behandlung  der  Erkrankungen  des  Antrum 
Highmori.     [Berliner  Klin.  Wochenseh.     1888. ) 

—  Kraitse.  Discussion  liber  das  Empyem  der  Highmorshohle.  [Berliner 
Klin.  Wochenseh.     1887.) 

L.  A.  Weil.  Eiterdui'chbruch  nach  der  Fossa  canina  des  Oberkiefers,  falschlich 
als  Empyema  Antri  Highmori  diagnosticirt.     [Odontoskop.     1893.) 

—  Eyssautier.  Currettage  du  sinus  Maxillaire  pour  un  cas  rebelle  d'abces 
chronique  de  cette  cavite.     (Grenoble  Imp.     1891) 

P.  Eitter.  Ein  Fall  eines  ins  Antrum  hineingewucherten  JSTasenpolypen. 
[Deut.  Monatssch.  f.  Zahnheilk.     1893.) 

M.  Schmidt.  The  Diagnosis  and  Treatment  of  Diseases  of  the  Antrum  of 
Highmore.     [Br.  Jour,  of  Dent.  Sci.     1889.) 

A.  W.  W.  Baker.     Abscess  of  the  Antrum.     [Br.  Jour,  of  Dent.  Sci.     1889.) 
A.  B.  SiBSON.     Antral  Diseases.     [Br.  Jour,  of  Dent.  Sci.     1893.) 
H.  Sewell.     Empyema  of  the  Antrum.     [Monthly  Review  of  Dental  Surgery. 
1891.) 

F.  Semon.  Some  Points  in  the  Etiology,  Diagnosis,  and  Treatment  of  Empy- 
ema of  the  Antrum.      (Trans.  Odont.  Soc.  Gr.  Britain.     1889.) 


LITERATURE.  661 

CHAPTEK   XLIV. 

N.  Jacobson.  The  Early  Diagnosis  and  Treatment  of  Tumors.  {Dmtal 
Cosmos.     Vol.  XXXI.) 

S.  KousH.  Differential  Diagnosis  between  Benign  and  Malignant  Growths  in 
the  Oral  Cavity.     {Dental  Cosmos.     Vol.  XXXVI.) 

CHAPTEE   XL VI. 

T.   W.    Brophy.     Affections  of  the    Salivary    Glands,    etc.     {Dental   RcvieuK 
1891.) 
J.  S.  Smith.    Cystic  Tumor  of  Upper  Jaw.    [Missouri  Dental  Journal.    1878.) 

—  Wheeler.     Large  Eanula,  etc.     [Missouri  Dental  Journal.     1883.) 

C.  H.   HuKGERFOKD.     Cystic   Abscess   in    a   Child.     [ArcJuves  of  Dentlsti-y. 
1884.) 
A.  Baker.     Dentigerous  Cyst.     [Archives  of  Dentistry.     1886.) 

—  Brtakt.     Cyst  in  the  Antrum.     [Dental  Cosmos.     Vol.  III.) 
W.  M.  Coates.     Large  Eanula.     [Dental  Cosmos.     Vol.  VII.) 
F.  Betton.     Eanula.     [Dental  Cosmos.     Vol.  X.) 

J.  Masox.     Cystic  Tumors  of  the  Jaws.     [Dental  Cosmos.     Vol.  VIII.) 

—  Napheys.     Eanula.     [Dental  Cosmos.     Vol.  VIII.) 

.     Cyst  in  the  Antrum,  etc.     (Pp.  159,  160.     Dental  Cosmos.     Vol. 

IX.) 

—  Bertiit.     Eanula.     [Dental  Cosmos.     Vol.  XI.) 

—  HuLKE.     Cystic  Tumor  of  the  Maxilla.     [Dental  Cosmos.     Vol.  XL) 

.     Eanula.     (Pp.  321,  326,  439,  550.     Dental  Cosmos.     Vol.  XII.) 

J.  E.  Garretsox.     Eanula,  etc.     [Dental  Cosmos.     Vol.  XII.) 

—  Hodges.     Dentigerous  Cyst.     [Dental  Cosmos.     Vol.  XIII. ) 
W.  S.  Bolles.     Dentigerous  Cyst.     [Dental  Cosmos.     Vol.  XIII.) 
W.  Tay.     Eanula.     [Dental  Cosmos.     Vol.  XIII.) 

—  Eamskill.  Salivary  Calculus  Obstructing  Wharton's  Duct,  etc.  [Dental 
Cosmos.     Vol.  XIII.) 

—  Verneuil.  Osseous  Cyst  of  the  Lower  Jaw.  [Dental  Cosmos.  Vol. 
XIV.) 

—  Waite.  Putty  Tumor  in  the  Situation  of  Eanula.  [Dental  Cosmos.  Vol. 
XIV.) 

C.   Heath.    Fibro-Cystic  Tumor  of  Lower  Jaw.    [Dental  Cosmos.    Vol.  XIV.) 
Professor  Briggs.     Fibro-Cystic  Tumor  of  Inferior  Maxilla.    [Dental  Cosmos. 
Vol.  XIV.) 

—  GuERSANT.     Eanula.     [Dental  Cosmos.     Vol.  XIV.) 
W.  M.  Barker.     Eanula.     [Dental  Cosmos.     Vol.  XIV. ) 

J.  Machwuerth.     Alveolar  Cyst.     [Dental  Cosmos.     Vol.  XV.) 

J.   F.  Babcock.     Cysto-Sarcoma  in  the  Upper  Jaw.     [Dental  Cosmos.     Vol. 

XVI.) 

A.  W.  Stocks.     Dentigerous  Cyst  in  the  Upper  Jaw.     [Dental  Cosmos.     Vol. 

XVII.) 

M.  TiLLAUX.     Acute  Eanula.     [Dental  Cosmos.     Vol.  XVII.) 
M.  Forget.     On  Eanula.     [Dental  Cosmos.     Vol.  XVII. ) 

.     Sub-Lingual  Mucous  Cyst.     [Dental  Cosmos.     Vol.  XVII.) 

A.  CoLEMAK.     Dentigerous  Cyst.     [Dental  Cosmos.     Vol.  XVIII.) 

— .     Eanula.      [Dental  Cosmos.     Vol.  XIX.) 

_  .     Cyst  of  the  Upper  Jaw.     [Dental  Cosmos.     \o],  X^X.) 

46 


662  LITERATURE. 

X    MtJLLER.    On  Ranula  in  Xew-Born  Children.     [Dental  Cosmos.     Vol.  XX.) 

—  Stokes.     Dentigerous  Cystic  Tumor.     {Dental  Cosmos.     Vol.  XXII.) 
.     Cyst  of  the  Upper  Jaw.     [Dental  Cosmos.     Vol.  XXI.) 

—  .     Eanula.     [Dental  Cosmos.     Vol.  XXI.) 

"W.  T.  Wheeler.     Large  Eanula.     [Dental  Cosmos.     Vol   XXIII.) 
.     Serous  Cysts.     [Dental  Cosmos.     Vol.  XXIII.) 

—  .     Eanula,  etc.     [Dental  Cosmos.     Vol.  XXIV.) 

C.  B.  LoCK"WOOD.     Eanula      [Dental  Cosmos.     Vol   XXIV.) 
F.  S.  Eve.     Some  Points   in  tlie   Pathology   of  Cystic  and    Encysted   Solid 
Tumors  of  the  Jaw.     [Dental  Cos?nos      Vol.  XXVIII.) 

A.  Baker.     Dentigerous  Cyst.     [Dental  Cosines.     Vol.  XXIX.) 

E.  E.  MrLLETT.  A  Case  of  Dentigerous  Cyst.  [Dental  Cosmos.  Vol. 
XXXV.) 

—  Eossl.  Bemerkungen  iiber  die  an  der  Spitze  der  Backenzahnwurzeln 
entwickelten  Cysten.     [De-r  Zahnarzt.     1853.) 

A.  Hartui^g.  Kiefercyste  in  Eolge  abnorm  entwickelter  Zahne.  [Deut. 
Monatssch.  f.  Zahnheilk.     1883.) 

C.  KtJH^cs.  Cyste  iMilchzahngebilde  enthaltend.  [Deut.  Monatssch.  f. 
Zahnheilk.     1885.) 

—  EiTTER.  Cyste  am  Proc.  Alveol.  des  Oberkiefers.  [Deut.  Monatsschr.  f. 
Zahnheilk.     1885.) 

—  GrAKTifER.     tjber  Eanula.     Heidelberg,  1890. 

—  XEniAXif .  tJber  die  Entstehung  der  Eanula,  etc.  [Arch.  f.  Klin.  Chirur- 
yie.     Vol.  XXX.) 

F.  Bartels.  tJber  Kiemengangcysten  und  Kiemenganglisteln.  Eudolph- 
stadt,  1891.) 

E.  Bejs'eke.     Zur  Genese  der  Kiefercysten.     Halle,  1891. 

C.  BouYET.  Etude  critique  sur  la  Pathogenic  des  Kystes  des  machoires. 
(These.)     Paris,  1891. 

A.  Backer.  Notes  on  the  Pathology  of  a  Dentigerous  Cyst.  [Dublin  Jour. 
of  Med.  Sci.     1891.) 

—  Krtjse.  tJber  die  Entwicklung  Cystischer  Geschwiilste  im  Unterkiefer. 
[Virchow's  Arch.     Bd.  CXXIV.) 

C.  Fackeldey.     tJber  Kiefercysten.     Halle,  1869. 

—  MAirASSEi>*.  Zur  Lehre  von  der  Spiroch»ta  Obermeieri.  (Cyste  ausge- 
hend  von  der  Highmorshohle.)     [Med.  Wochenschr.     Petersburg,  1876.) 

F.  S.  Eve.  Cystic  Tumoi-s  of  the  Jaws,  and  the  Etiology  of  Tumors.  [Br. 
Jour,  of  Dent.  Sci.     1883.) 

T.  S.  Carter.     Dentigerous  Cyst.     [Monthly  Review  of  Dent.  Surg.     1888.) 
W.  W.  Baker.     Note  on  the  Pathology  of  a  Dentigerous   Cyst.     [Monthly 
Review  of  Dent.  Surg.     1891.) 

—  Coleman.     On  Cystic  Tumors.     (Trans.  Odont.  Soc.  Gr.  Britain.     1864.) 
C.  Wedl  und  Heider.     tJber  eine  Cyste  des  Oberkiefers   nebst  klinischen 

Bemerkungen  iiber  Cysten.     [Deut.  Vier.  Jahrsch.  f.  Zahnheilk.     1865.) 

—  Falkso".     Cystom  des  Unterkiefers.     [Virehovys  Arch.     Bd.  LXXVI.) 
V.  Eeckli>^ghausen.      tJber    die     Eanula,    etc.      [Virchow's    Arch.      Bd. 

LXXXIV.) 

J.  Parreidt.  tJber  Zahn-  und  Kiefercysten.  [Deut.  Monatsschr.  f.  Zahn^ 
heilk.     1887.) 

—  Eedard.  Uber  einen  Fall  von  Zahntragender  Dermoidcyste.  {Deut. 
^^i.l(at^schr.f.  Zahnheilk.     1887.) 


LITERATURE.  663 

J.  Parreidt.  Beitrag  zur  Diagnose,  Aetiologie,  und  Behandlung  der  Zahn- 
cysten.      [Deut.  Monatssc/i.  f.  Za/cnheilk.     1889.) 

W.  DiECK.  Irritationscyste,  hervorgerufen  durch  einen  aLnorra  gelagerten 
bleibendeii  Zahn.     [Dent.  Monatsschr.  f.  ZaJmheiik.     1889.) 

—  Schneider.  Empyem  der  Kieferholile,  etc.  {Dcut.  Mo/iaisschr.  f.  Zahn- 
heilk.     1890.) 

F.  Eahx.     Beitrag  zur  Kenntniss  der  Kanula.     Tubingen,  1891. 

—  Part-sch.     tjber  Kiefercysten.     [Deut.  Monatsschr.  f.  Zahnheiik.     1892.) 

G.  KiLiAX.  Meine  Erfahrungen  iiber  Kieferhohleneiterungen.  [MuncJmer 
Med.   Wochenschr.     1892.) 

A.  Gate.  Des  Kyotes  dermoides  et  mucoide.s  medians  de  la  langue  et  du 
plancher  de  la  bouche.     (These.)     Paris,  1892. 

—  Broe.sike.     Zur  Casuistik  der  Cystome.     Berlin.  1874. 

—  Zahx.  tJber  viele  Falle  von  KiemengangcN-steu.  [Deut.  Zeltschr.  f.  Chi- 
rurgie.     Bd.  XXII.) 

A.  Krtjse.  tJber  die  Entstehung  cystischer  Gesch-^-ulste  im  Unterkiefer. 
(  Virchow's  Arch.     Vol.  CXXIY.) 

—  Neumaxn.  Ein  Beitrag  zur  Kenntniss  der  Ranula.  [Langenheck' s  Arch, 
Yol.  XX.) 

—  SoNXEXBTjRG.  Uber  Sitz  und  Behandlung  der  Eanula.  {Arch.f.  Kli?i. 
Ghirurgie.     Vol.  XXIX.) 

F.  BrrsCH.  Centrale  Epitheliome  mit  Cystenbildung.  {Berliner  Klin.  Wochen- 
schr.    1877. ) 

CHAPTER    XLYII. 

A.  E.  Baldwin.     Tumors  of  the  Mouth  and  Jaws.     [Dental  Revieiv.     1888.) 
AY.  Fergussox.     Recurrent  Osseous  Tumor.     [Dental  Cosmos.     Yol.  XY.) 

.     Cancer  of  Upper  Jaw.     [Dental  Cosmos.     Yol..  XYI. ) 

.     Tumor  of  Upper  Jaw.     [Dental  Cosmos.     Yol.  XYI.) 

—  Bertolet.  Interesting  Specimen  of  Epulis.  [Dental  Cosmos.  Yol. 
XYI.) 

—  .     Tumor  of  Both  Upper  Jaws.     [Dental  Cosmos.     Yol.  XYI.) 

—  .     Sublingual  Tumor.     [Dental  Cosmos.     Yol.  XYI.) 

—  BuTLix.  Osteoma  of  the  Superior  Maxilla.  [Dental  Cosmos.  Yol. 
XYII.) 

F.  JMasox.  Anomalous  Tumors  Caused  by  Imbedded  Teeth.  [Dental  Cosmos. 
Yol.  XX. ) 

J.  E.  Mears.  Spindle-Cell  Sarcoma  of  the  Lower  Jaw.  [Dental  Cosmos. 
Yol.  XXII.) 

M.  LoxGSTRETH.     Myeloid  Sarcoma  of  .Jaw.     [Dental  Cosmos.     Yol.  XII.) 

E.  Masox.     Sarcoma  of  Jaw. — Death.     [Dental  Cosmos.     Yol.  XII.) 

—  Heath.  Twenty-five  Tears'  History  of  a  Maxillary  Tumor.  [Dental 
Cosmos.     Yol.  XXII.) 

J.  F.  Thompsox^.  Carcinoma  Simulating  Eanula.  [Dental  Cosmos.  Yol. 
XXII.) 

IS".  Sex'x.  The  Pathology  and  Treatment  of  Epulis.  [Dental  Cosmos.  Yol. 
XXII.) 

C.  Macx'amara.     Sarcoma  of  Upper  .Jaw.     [Dental  Cosmos.     Yol.  XXIY.) 

—  Gaddes.     Recurrent  Epulis.     [Dental  Cosm,os.     Yol.  XXIY.) 
.     Ossified   Sarcoma   of    the    Lower   Jaw.      [Dental    Cosmos.      Yol. 

XX  Y.) 


664  LITERATURE. 

E.  TiLLEY.     Osteoma.     {Denial  C.osu>o».     \o\.  XXVIII.) 

C.  Heitzmaxx  and  F.  Abbott.     Contributions  to  the  Knowledge  of  Tumoi-s 

of  the  Jaws.     {Dental  Cosmos.     Vol.  XXX.) 

A.  Wk(?tlake.     a   Case    of    Giant-Cell    Sarcoma.       [Dental    Cosinos.      "S'ol. 

XXXI.) 

A.  G.   Geester.     Operative  Dissemination.     [N.  Y.  Med.  Jour.) 

J.   Leclerc.     Contribution  a  I'etude  des  tumeurs  du  voile  du  palais  et  de  la 

voute  palatine.     (These.)     Montpellier  Imper.  Hamelin  Freres,  1892. 

P.   S.  "WiNDMULLER.     Beitrag  zur  Casuistik  der  Kiefertumoren.     Gottingen, 

1891. 

—  HiLDEBRAXD.  Beitrag  zur  Lehre  von  den  durch  abnomie  Zahnentwicklung 
bedingten  Kiefertumoren.     [Deut.  Zeitschr.  f.  Chiruryie.     Bd.  XXXII.) 

J.   C.  Scott.     Cancerous  Tumor.     {Johnston's  Dental  Miscellany.     1878.) 

G.  Law.son.  Large  Cartilaginous  Tumor.  {Johnston's  Dental  Miscellany. 
1878.) 

W.  H.  Atkinson.  Tumors  of  the  Mouth.  (Trans.  Dent.  Soc.  of  the  State 
of  K.  Y.     1873.) 

H.  Hancock.     tJber  Geschwiilste  des  Oberkiefers.     {Der  Zahnarzt.     1856.) 

C.  FocK.  tJber  zwei  Falle  vou  Knochengeschwiilsten  am  Alveolarfortsatz 
des  Oberkiefers.     {Der  Zahnarzt.     1856.) 

J.  EouYER.  tJber  die  Tumoren  der  Gaumenregion,  welche  durch  Driisen — 
Hypertrophie  gebildet  werden.     {Der  Zahnarzt.     1857.) 

C.  Heath.     The  Diseases  of  the  Jaw. 

—  HoFMOKL.  tJber  Resection  des  Unterkiefers,  mit  Rueksicht  auf  88  darauf 
beziigliche  Krankheitsfalle.     [Wiener  Med.  Jahrb.     1871.) 

Th.  Billroth.     Elemente  der  Allgemeinen  chirurgischen  Pathologie.     1868. 
J.Paget.     Tumors  of  the  Palate.     (St.  Bartholm  Hosp   Rep.     1886.) 

—  Allgeyer.  tjbercentrale  Epithelgeschwiilste  des  Unterkiefers.  [KUnische 
Beitr.     1886.) 

O.  Weber.     Handb.  der  allgem.  und  operativen  Chirurgie.     Bd.  III. 

—  Ohlmann.  Beitrage  zur  Statistik  der  Oberkiefergeschwiilste.  [Arch.  f. 
Klin.  Chirurgie.     Bd.  XYIII.) 

A.  Winiwarter.     Beitrage  zur  Statistik  der  Carcinome.     Stuttgart,  1878. 

—  BiRNBAtTM.  Beitrage  zur  Statistik  der  Kiefergeschwiilste.  [Dent.  Zeitsch. 
f.  Chirurgie.     Bd.  XXYIII.) 

—  Satjrel.     Tumors  of  the  Gums.     [Am  Jour,  of  Dent.  Sci.     1858.) 
E.   C.  Chase.     Epulis.     [Missouri  Dent.  Jour.     1872.) 

G.  Rabitoy.     Bone  Tumor  of  Lower  Jaw.     [Missouri  Dent.  Jour.     1876  ) 
G.  Lawson.     Large  Cartilaginous  Tumor  of  Lower  Maxilla.     [Missouri  Dent. 

Jour.     1878.) 

C.  E.  Xelson.     Dental  Tumor  of  Jaw.     [Missouri  Dent.  Jour.     1882.) 

J.  S.  Amoore.     Sarcomatous    Growth   in    the    Upper   Jaw.     [Missouri  Dent. 

Jour.     1882.) 

O.  J.  CosKERY'.     A  Case  of  Sarcoma  of  Lower  Jaw.     [Archives  of  Dentistry. 

1885.) 

J.  A.  Wyeth.     Sarcoma  of  the  Lower  Jaw.     [Archives  of  Dentistry.     1885.) 

T.  Bry'ANT.     Tumors.      [Dental  Cosmos.     Vols.  V  and  VI.) 

J,  E.  Garretson.     The  Tumors  of  the  Mouth.     {Dental  Cosmos.     Vols.  VII 

and  VIII.) 

.     Epulis.     {Dental  Cosmos.     Vol.  VIII.     Pp.  181  and  448.) 

,     Large  Epulis.     {Dental  Cosmos.     Vol.  VIII.     P.  103.) 


LITERATURE.  665 

S.  J.  A.  Salter.  On  Papillary  Tumors  of  the  Gum.  [Dental  Cosmos. 
Vol.  VIII.) 

J.  S.  Smith.     Vascular  Tumor.     [Dented  Cosmos.     Vol.  IX.) 

C.  Heath.     Osteo-Sarconia  of  Lower  Jaw.     [Dental  Cosmos.     Vol.  X.) 

W.  Fergusson.     Ivory  Tumor  of  the  Upper  Jaw.    [Dental  Cosmos.    Vol.  X.) 

R.  ViRCHOw.     Neuroma.     [Dental  Cosmos.     Vol.  X.) 

J.  Martin.     Epulis.     [Dental  Cosmos.     Vol.  X.) 

—  Mears.     Medullary  Carcinoma  of  Antrum.     [Dental  Cosmos.     Vol.  XII.) 
R.  A.  KiXLOCH.     Sarcomatous  Fibroma,  etc.     [Dental  Cosmos.     Vol.  XII.) 
S.  W.  Gross      Horny  Tumor  of  Lower  Lip.     [Dental  Cosmos.     Vol.  XII.) 
L.  A.  Sayre.     Fibro-Serous  Cyst  of  Jaw.     [Dental  Cosmos.     Vol.  XIII.) 

E.  Neumann.     Gummata  Syphilitica.     [Dental  Cosmos.     Vol.  XIII.) 

S.  W.  Gross.     Tumor  of  the  Lower  Jaw.     [Dental  Cosmos.     Vol.  XIII.) 

J.  Syme.     Uber  Kiefergeschwulste.     [Der  Zahnarzt.     1856.) 

C.  Barrow.     LTber  die  nachtheilige  Wirkung  im  Alveolarfoi-tsatz  zuriickge- 

bliebener  Zahnreste.     [Der  Zahnarzt.     1859.) 

C.  E.  Truman.     Contribution.s  from  the  Dental  Department  of  St.  Thomas's 

Hospital.     Two  Cases  of  Epulis,  etc.     Two  Cases  of  Abscess  Pointing  on  Face  at 

Root  of  Nose,  just  below  the  Eye.     Case  of  Eruption  of  Canine  under  the  Chin. 

[Br.  Jour,  of  Dent.  Sci.     1893.) 
"W.  Thorburn.     Tumors  of  the  Jaw   and   Gums.      [Br.   Jour,   of  Dent.   Sci. 

1892.) 
S.  A.  CoxoN.     A  Case  of  Cystic  Sarcoma  of  the  Superior  IMaxilla.     [Br.  Jour. 

of  Dent.  Sci.     1892.) 

F.  F.  BuRGHARD.  On  Some  Cases  of  Epulis.  (Trans.  Odont.  Soc.  Gi\  Britain. 
1888) 

C.  Heath.  On  Epithelioma  of  the  Jaw.  (Trans.  Odont.  Soc.  Gr.  Britain. 
1891.) 

J.  ArkOvy.  On  Papilloma  of  the  Oral  Cavity.  (Trans.  Odont.  Soc.  Gr. 
Britain.     1880.) 

CHAPTER   XLVIII. 

Ellenberger  und  Baum.  Ein  Beitrag  zu  dem  Kapitel  Zahnretention  und 
Zahnrudimeute.     [Arch.  f.  Anat.  unci  Physiol      1892.) 

L.  A.  Weil.  Doppelseitige  Zwillingsbildung  der  Mittleren  oberen  Schneide- 
zahne.     [Deut.  3Ionatsschr.  f.  Zah?iheilk.     1893.) 

R.  Baume.     Zahnmissbildungen.     [Deut.  Vier.  Jahrschr.  f.  Zahnheilk.     1874.) 

R.  Baume.     Ein  Odontom.     [Deut.  Vier.  Jahrschr.  f.  Zahiiheilk.     1874.) 

—  Hermann.  Anomal  gebildete  Zahne.  [Deut.  Vier.  JahrscJtr.  f.  Zahnheilk. 
1874.) 

J.  V.  Schneider.  Zwei  FiiUe  von  Schmelzlosen  Zahnmissbildungen.  [Deut. 
Vier.  Jahrschr.  f.  Zahnheilk.      187K.) 

—  Schwartzkopf.  Ein  Fall  von  Zwillingsbildung  zweier  vorderer  Schneide- 
zahne.     [Deut.  Vier.  Jahrschr.  f.  Zahnheilk.     1882.) 

—  Geisselbrecht.  Zahnmissbildung  und  dritte  Dentition.  [Deut.  Vier. 
Jahrschr.  f.  Zahnheilk.     1882.) 

—  MoNTiGEL.  Tiber  zwei  Falle  seltener  Dentitionsanomalie.  [Deut.  Monats- 
schr.  f.  Zahnheilk.     1888.) 

—  Brunsmann.  Tiber  einige  Zahnanomalien.  [Deut.  Monatsschr.  f.  Zahn- 
heilk.    1889.) 


666  LITERATURE. 

A.  Mayer.  Ein  Fall  von  Cenientverschmelzung  dreier  Zahiie.  {Deut. 
Monatsschr.  f.  ZahnheUk.     1890.) 

—  Herrmann.  Eine  Milclizahnanomalie.  [Deut.  Mdnaisschr.  f.  ZahnheUk. 
1891.) 

A.  Sternfeld.  Aiiomalieii  der  Zaliiie,  in  Handb.  der  Zahnlieilk.,  von  J. 
Scheff,  Jr.     Wien,  1891. 

J.  Scheff,  Jr.  Eetention  ;  Kudimentarzahne  etc.  In  Handb.  der  Zahnhoilk. 
Wien,  1891. 

M.  Schlenker.  Schmelzti'opfen,  aussere  Odontome  Exostosen.  In  Handl). 
der  Zahnheilk.,  von  J.  Scheff,  Jr.     Wien,  1891. 

—  Part.sch.  tJber  zwei  Falle  von  Odontomen.  [Deut.  Monatsschi- .  f.  Zalm- 
heilk.     1892.) 

B.  Salzer.     Verscliiedenes  aus  der  Praxis.     [Odontoskop.     1893.) 

A.  H.  Thompson.  The  Missing  Teeth  of  Man.  {Dental  Cosmos.  Vol 
XXXVI.) 

M.  L1P8CHITZ.  Eine  seltene  Zahnanomalie.  [Dent.  Monatsschr.  f.  ZahnheUk. 
1893.) 

.     A  Child  with   Teeth  in  its  Nose      {Johnston's  Dental  Miscellany 

1874.) 

J.  A.  OsMtTN.  Fnerupted  Teeth  in  the  Koof  of  the  Mouth.  {Johnston's 
Dental  Miscellany      ]880.) 

—  ■ .     Anomalous  Teeth.     {Am.  Jow\  of  Dent.  Sci.     1843.     P.  150.) 

—  .     Anomalous  Teeth.     {Am.  Jour,  of  Dent.  Sci.     1844.     P.  63.) 

S.  Malet.     Osseous  Union  of  Teeth.     {Am.  Jour,  of  Dent.  Sci.     1856.) 

J.  J.   Patrick.     Osseous  Union  of  Teeth.     {A)n.  Jour,  of  Dent.  Sci.     1856.) 
.     Osseous  Union  of  Teeth.     {Am.    Jour,  of  Dent.  Sci.     1857.    Pp. 

451  and  600.) 

I.  C.   Gray.     An  Odontoid.     {Missouri  Dent.  Jour.     1875.) 

T.  W.  Eeed.     Union  of  Teeth.     {Missouri  Dent.  Jour.     1876.) 

H.  L.  Sage.     Nodules  on  Teeth.     {Missouri  Dent.  Jour.     1876.) 

G.  V.  Black.     Odontome.     {Missouri  Dent.  Jour.     1880.) 

E.  Schwarzkopf.     Union  between  Both  Upper  Central  Incisors   with   the 

Laterals.     {Missouri  Dent.  Jour.     1882.) 

U.  D.  Taylor.     Double  Teeth.     {Dental  Cosmos.     Vol.  I. ) 
.G.  J.  Stivers.     Mai-Development  of  Teeth.     {Dental  Cosmos.     Vol.11.) 
W.  N.  Amer.    Mal-Position  of  the  Canine  Teeth.    {Dental  Cosmos.    Vol.11.) 
S.  H.  Guilford.     A  Dental  Anomaly.     {Dental  Cosmos.     Vol.  XXV.) 

C.  W.  Stainton.     Crownless  Teeth.     {Dental  Cosmos.     Vol.  XXXIV.) 

V.  Jarre.  Congenital  Absence  of  Teeth  in  a  Subject  Twelve  Years  Old. 
{Dental  Cosmos.     Vol.  XXXIV. ) 

L.  H.  Hollander.  Demonstration  einigerPathologischer  Kieferprajjarate  und 
einiger  Zahnanomalien.      {Verhand.  d.  Deut.  Odont.  Gesell.     Bd.  II.) 

E.  BuscH.  tJber  Verschmelzung  und  Verwachsung  der  Zahne  des  Milchge- 
bisses  und  des  bleibenden  Gebisses.     {Verhand.  d.  Deut.  Odont.  Gesell.     Bd.  V.) 

—  Hohl.  Einiges  iiber  die  Entstehung  der  "freien"  Odontome.  {Deut. 
Vier.  f.  ZahnheUk.     1868.) 

C.  Wedl.  Untersuchung  einer  Zahnmis.sbildung  am  Unterkiefer.  {Deut. 
Vier.  Jahr.f.  ZahnheUk.      1869.) 

J.  V.  Metnitz.     Odontomes.     {Dental  Review.     1889.) 

Z.  M.  Kreider.  Osseous  Union  of  Two  Temporary  Teeth.  {Am.  Jour,  of 
Dent.  ScL     1851.) 


LITERATURE.  667 

.     Osseous  Union  of  Teeth.     {A)/i.  Jour,  of  Dent.  Sci.     1858.) 

E.  H.  AxDREWS.     Extraordinary  Successive  Development  of   Teeth.      [Am. 

Jour,  of  Dent.  Sci.     1858  ) 

E.  S.  Talbot.     A  Wandering  Supernumerary  Tooth.     (Indep.  Pract.     1884.) 

W.  H.  FoLKER      Tootli  in  Upper  Lip.     {Dental  Cosmos.     Vol.  IX.) 

M.  GuE>s"iOT.     Teeth  at  Birth.     {Dental  Cosmos.     Vol.  IX.) 

M.   Broca.     Odontomes.     {Denial  Cosmos.     Vol.  X.) 

W.  P.  EiCE.     Dental  Anomaly.     {Dental  Cosmos.     Vol.  XIII.) 

G.  S.  Fox'KE.     Osseous  Union  of  Teeth.     {Dental  Cosmos.     Vol.  XI^'.) 

.     Connate  Teeth.     {Dental  Cosmos.     Vol.  XV.) 

DE  H.  Hall.     Malposition  of  a  Tooth.     {Dental  Cosmos.     XXVI.) 

J.  A.  Daly.     Dental  Anomalies.     {Dental  Cosmos.     Vol.  XXX.) 

W.  Adams.     Dental  Anomaly.     {Dental  Cosmos.     Vol.  XXXI.) 

E.   Abbott.     Eare  Dental  Anomalies.     {Dental  Cosmos.     Vol.  XXXIII.) 

C.  W.  ScHMEDlCKE.     Uber  Verschmolzene  Zahue.     (Z)e?'  Zahnarzt.  1846.) 

C.  W.  ScHMEDiCKE.     Das  Angebliche  Verwachsen  der  Zahnwurzeln  mit  den 

Alveolen.     {Der  Zahnarzt.     1846.) 

L.  J.  Melicher.    tjber  zusammengewachsene  Zahne.    {Der  Zahnarzt.    1847.) 
M.     HoFFA.     Beschreibung  zweier  anomal  gebildeten  Zahne.     {Der  Zahnarzt. 

1849.) 
K.  Battme.     Seltsame    Zahnmissbildung.     {Dent.    Vier.    Jahrschr.   f.    Zahn- 

heilk.     1872.) 

E.  Baume.     Zwillingsbildung.     {Deut.  Vier.  Jahrschr.  f.  Zahnheilk.     1872) 
—  Fripp.     Three  Cases  of  Imperfect  Dentition  in  the  Same  Family.     {Jour. 

of  the  Br.  Dent.  Asso       1891.) 

L.  Hollander.    Impaction  eines  Milcheckzahnes  tief  im  Kiefer  bei  normalem 

Durchbruch  des  bleibenden  Eckzahnes      {Oestr.  Vngar.  Vier.  Jahrsch.     1892.) 
J.    Parkeidt       Mahlziihne    an    Stelle    der    zweiten    Praemolaren.      {Deut. 

Monatsschr.  f  Zahnheilk      1894) 
J.  A.  Briggs.     On  Malformation,     {Br,  Jour,  of  Dent.  Sci.     1889.) 
J.  W.  Dtjxkerlet.     Odontomes.     {Br.  Jour,  of  Dent.  Sci.     1892.) 

— .  .     Odontomes,  in  Trans.  Odont.  Soc.  Gr.  Britain.    1888. 

A.  S.  UjiTDERWOOD.     A  Eemarkable  Odontome.       {Monthly  Revieiv  of  Dental 

Surgery.     1882.) 
C.  S.  Tomes.   Description  of  an  Odontome.     (Trans.  Odont.  Soc.  Gr.  Britain.- 

1871.) 


INDEX. 


Ap.kasion,  mechanical,  309. 

causes  of,  309. 

secondary  dentine  in,  311. 
Abscess,  alveolar,  clinical  features  of,  455. 

blind  (chronic  purulent  circumscribed  peri- 
cementitis). 451. 
Absorption  of  temporai-y  teeth,  264. 

of  cementum  and  dentine  of  temporary 
teeth, 267. 

of  enamel  of  temporary  teeth,  270. 
Adenitis,  lymph,  460. 
Alveolar  process  of  lower  jaw,  10. 

of  upper  jaw,  4. 
Amelitis,  322. 
Ameloblasts,  breaking  up  of  the,  173,  186. 

definition  of  the,  126. 

development  of  the,  171. 
Ameloma,  tumor  of  the  enamel,  554. 
Anatomy,  general,  of  the  teeth,  39. 

of  the  teeth,  diagram  of  the,  40. 

of  the  teeth,  macroscopical,  16. 

morbid.     {See  microscopical  features  of.) 
Anomalies  of  the  dentine,  241. 

of  the  enamel,  205. 

of  the  papilla,  239,  242. 
Anomalous  though  not  pathological  formations 

in  the  teeth,  44,  205,  239. 
Anterior  dental  canal,  2. 

nasal  spine,  4. 

palatine  canal,  3. 
Antrum  of  Highmore,  1,  5. 

blood-vessels  and  glands  of,  7. 

communications  between  nasal  cavityand,6. 

empyema  of,  542. 

lining  membrane  of,  7. 

polypoid  growths  in,  545. 

shape  of,  5. 

variations  in  size  of,  6. 

walls  of,  5. 
Aphthfe,  ulceration  of  the  gum,  369. 
Arsenic,  the  eifects  of  upon  the  pulps  of  teeth, 

518. 
Articulation  of  the  teeth,  34. 
Atrophy  of  the  pulp,  of  the  nerves  of,  427. 

reticular,  419-425. 

sclerotic,  418-424. 


Basal  ridge  or  cingulum,  18. 
Basis-substance  of  bone,  51. 

o&cementum,  structure  of,  105. 

of  dentine,  structure  of,  41,  73,  80,  86, 133, 
138. 

of  enamel,  structure  of,  91,  96. 
Bicuspids  or  premolars,  general  characteristics 
of  the,  20. 

lower  and  upper,  characteristics  of  the,  20. 
Blood-vessels,  structure  of,  58. 

of  the  pericementum,  260. 

of  the  pulp,  43,  44,  248. 
Bone-tissue,  basis-substance  of,  51. 

canaliculi  of,  50. 

corpuscles  of  (lacunaj),  50. 

Haversian  systems  of,  51. 

lamellae  of,  51. 

new  formations  of  in  the  pericementum, 
475. 

new  formations  of  in  the  pulp,  289,  292,  303, 
307. 

trabeculse  of,  50. 

two  varieties  of,  49. 

Calcification  of  the  enamel,  173. 
deficient,  210,  216. 
of  dentine,  133. 
of  nerves  of  the  pulp,  429. 
of  pulp-tissue,  412,  420. 
Cancer,  or  carcinoma,  604. 

epithelioma  or  dermoid,  604. 
medullary,  607. 
Canine  fossa,  1. 
Canines,  cuspids,  or  eye-teeth,  description  of, 

19,  26,  28. 
Caries  of  the  teeth,  488. 
Abbott's  views,  489. 
acute,  496. 

begins  as  a  chemical  process,  490. 
chronic  a  mere  chemical  process,  495. 
difference  of  resistance  to,  490. 
etiology  of,  489. 
micro-organisms  in,  493,  495. 
Nasmyth's  membrane  in,  493. 
of  a  piece  of  hippopotamus  tooth,  494. 
of  cement,  500. 

47  669 


670 


INDEX. 


Caries  of  dentine,  493.   . 
of  enamel,  491. 
pigmentation,  491 
re-establislies  tlie  protoplasmic  condition 

of  the  tissue.?,  492. 
results  of  investigations,  502. 
starting-points  of,  489. 
the  influence  of  food  On,  489. 
Miller's  views,  503. 
accompanying  phenomena  of,  506. 
of  cement,  505,  514. 
of  dentine.  504,  510. 
of  enamel,  5ii3,  508. 
physical  phenomena  of,  503. 
pigmentation  of  the  tissues  in,  507. 
the  micro-organisms  of,  515. 
results  of  investigations  of,  516. 
the  healing  process  in,  517. 
Carious  cavities,  examination  for,  282. 
Cementitis  and  eburnitis,  370,  457,  467. 
Cementum,  the,  43, 101, 110.  . 

absorption  of  the,  267. 
basis-substance  of  the,  102. 
corpuscles  of  the,  43. 
h^matoidin  clusters  in  the,  463. 
osteoid,  114. 

the  development  of,  227. 
the  minute  structure  of,  101, 108. 
the  minute  structure  of  the  neck,  83, 105, 

119. 
the  structure  of  devitalized,  123. 
Classification  of  the  diseases  of  the  pericemen- 
tum, 432. 
of  the  diseases  of  the  pulp,  382. 
Clinical  and  anatomical  features  of  tumors  in 

general,  546. 
Cold  and  heat  in  diagnosis,  286. 
Colloid  degeneration  of  the  pulp,  431. 
Connective  tissue,  development  of,  58. 

varieties  of,  46. 
Constitutional  diseases  diagnosed  by  the  changes 
in  the  teetb  and  their  surroundings,  277. 
Coronoid  and  condyloid  processes,  12. 
Cysto-adenoma,  601. 
Cysts,  alveolar,  563. 

bony  new  formations  in,  572. 

classification  of,  560. 

definition  of,  560. 

dental  or  dentigerous,  561. 

epithelial,  560. 

in  the  antrum,  566. 

in  the  oral  cavity,  559. 

inflammatory,  564. 

mucoid,  561. 

papillary  vegetations  in  wall  of,  564. 

(ranula),  560. 

Defects,  congenital,  in  enamel,  216.     • 
Degenerations  and  atrophies  of  the  pulp,  412. 

colloid,  of  the  pulp,  431. 

fatty,  of  the  pulp,  431. 
Dentine,  absorption  of  the,  267. 

anomalies  of  the,  241. 

basis-substanee  of  the,  41,  73,  80,  86, 133, 139. 


Dentine,  calcification  of  the,  134. 

canaliculi,  development  of  the,  135. 

canaliculi  and  course  of  the,  41,  133. 

chemical  constituents  of  the,  41. 

development  of  the,  129,  139. 

fibers,  development  of  the,  131. 

fibers,  or  "Tomes's"  fibers,  42. 

first  trace  of  papilla  of  the,  129. 

formations  of  globular  territories  in  the, 
135. 

granular  layer  of  the,  42. 

interglobular  spaces  in  the,  44,  135. 

interzonal  layer  of  the,  42. 

methods  of  preparing  microscopical  speci- 
mens of  the.  69,  76. 

minute  structure  of  the,  69. 

nutrition  of  the,  270. 

physiology  of  the,  271. 

reaction  of  the,  upon  fillings,  320. 

recalcifieation  of  softened,  272. 

secondary  formations  of,  289,  292,  305,  311. 

sensitiveness  of  the,  272. 

structure  of  devitalized,  80,  273. 

tumors  of  the,  odontoma,  553. 
Development,  faulty,  194. 

of  bone-tissue,  64. 

of  teeth  in  embryos  afi'ected  with  rhachitis, 
232. 

of  the  ameloblasts,  171. 

of  the  cementum,  227. 

of  the  connective  tissue,  58. 

of  the  dentine,  129, 139. 

of  the  enamel,  148, 180. 

of  the  enamel-cord  at  the  sixth  week,  149. 

of  the  enamel-cord  into  the  enamel-organ, 
149. 

of  the  enamel-fibers,  174. 

of  the  enamel-organ  at  two  months,  150. 

of  the  enamel-organ  at  three  months,  151. 

of  the  enamel-organ  at  three  and  one-half 
months,  154. 

of  the  enamel-organ  at  four  months,  155. 

of  the  enamel-organ  at  five  months,  156. 

of  the  enamel-organ    at   six    and   seven 
months,  169. 

of  the  lower  maxilla,  12. 

of  the  upper  maxilla,  8. 

of  the  stellate  reticulum  and  stratum  inter- 
medium, 161. 
Diagnosis,  general,  of  the  diseases  of  the  teeth, 
274. 

heat  and  cold  in,  286. 

light  in,  287. 

of  acute  non-purulent  apical  pericementitis, 
437. 

of  acute  non-purulent  circumscribed  peri- 
cementitis, 435. 

of  acute  non-purulent  diffuse  pericemen- 
titis, 438. 

of  acute  non-purulent  marginal  pericemen- 
titis, 433. 

of  acute  non-purulent  partial  pulpitis,  385. 

of  acute  non-purulent  total  pulpitis,  386. 

of  acute  purulent  apical  pericementitis,  443. 


INDEX. 


671 


Diagnosis  of  acute  purulent  diffuse  pericemen- 
titis, 444. 

of  acute  purulent  pulpitis,  38S. 

of  alveolar  cysts.  563. 

of  calcification  of  the  pulp,  412. 

of  cementitis  and  eburnitis,  457. 

of  chrouie  purulent  apical  pericementiiis. 
453. 

of    chronic  purulent  circumscribed    peri- 
cementitis (blind  abscess),  451. 

of  chronic  purulent  diffuse  pericementitis, 
454. 

of  chronic  purulent  marginal  pericemen- 
titis (pyorrhoea  alveolaris).  447. 

of  chronic  purulent  pulpitis,  392. 

of  cysts  in  the  antrum,  545. 

of  cysts  in  the  oral  cavity,  559- 

of  dental  or  dentigerous  cysts,  561. 

of  eburnifications  and  ossifications  of  the 
pulp,  416. 

of  empyema  of  the  antrum,  543. 

of  gangrene  of  the  pulp,  dry,  396. 

of  gangrene  of  the  pulp,  moist,  394. 

of  hyperplasia  of  the  pulp,  partial,  389. 

of  hyperplasia  of  the  pulp,  total,  3^0. 

of  hyperplastic  diffuse  pericementitis,  441. 

of  hyperplastic  partial  pericementitis,  440. 

of  inflammatory  cyst,  564. 

of  irritation  of  the  pulp,  384. 

of  lymphadenitis,  460. 

of  necrosis  of  the  jaw-bone,  536. 

of  periostitis,  osteitis,  andosteomyeli  is,  458. 

of  ranula,  560. 

of  reticular  atrophy  of  the  pulp,  419. 

of  sclerotic  atrophy  of  the  pulp,  418. 

of  tumors  in  general,  549. 

of  tumors  of  the  jaws,  573. 

the  sense  of  smell  in,  285. 

the  sense  of  touch  in,  281. 

transillumination  in,  287. 
Differential  diagnosis  of  acute   non-purulent 
apical  pericementitis,  437. 

of  acute  non-purulent  circumscribed  peri- 
cementitis, 436. 

of  acute  non-purulent  diffuse  pericemen- 
titis. 439. 

of  acute  non-purulent  marginal  pericemen- 
titis, 434. 

of  acute  non-purulent  partial  pulpitis,  386. 

of  acute  non-pm-ulent  total  pulpitis,  387. 

of  acute  purulent  apical  pericementitis,  443. 

.  of  acute  purulent  diffuse  pericementitis,  445. 

of  acute  purulent  pulpitis,  388. 

of  alveolar  abscess,  457. 

of  calcifications  in  the  pulp,  413. 

of  chronic  purulent  apical  pericementitis, 
453. 

of    chronic  purulent   circumscribed   peri- 
cementitis, 452. 

of  chronic  purulent  diffuse  pericementitis, 
454. 

of  chronic  purulent  marginal  pericemen- 
titis, 449. 

of  chronic  purulent  pulpitis,  393. 


Differential  diagnosis   of  eburnifications    and 
ossifications  of  the  pulp,  417. 

of  empyema  of  the  antrum,  545. 

of  gangrene  of  the  pulp,  dry.  396. 

of  gangrene  of  the  pulp,  moist,  396. 

of  hyperplasia  of  the  pulp,  partial,  390. 

of  hyperplasia  of  the  pulp,  total,  391. 

of  hyperplastic  diffuse  pericementitis,  442. 

of  hyperplastic  partial  pericementitis,  440. 

of  irritation  of  the  pulp,  384. 

of  lymphadenitis,  461. 

of  necrosis  of  the  jaw-bones,  5i6. 

of  ozsena  of  the  nose,  545. 

of  periostitis,  osteitis,  and  osteomyelitis,  460. 

of  reticular  atrophy  of  the  pulp,  420. 
Discoloration  of  devitalized  teeth,  273. 
Diseases,  constitutional,  affecting  the  tissues  of 
the  teeth,  277. 

of  the  antrum,  542. 

of  the  gums,  363. 

of  the  maxillary  lymph-ganglia,  4(50. 

of  the  pericementum  and  alveolus,  clini- 
cal, 432. 

of  the  pericementum  and  alveolus,  morbid 
anatomy,  462. 

of  the  pulp,  clinical,  380,  412. 

of  the  pulp,  morbid  anatomy,  397,  420. 
Dwarf  teeth,  235,  609. 

Eburnipicatioxs  and  ossifications  of  the  pulp, 

413,  423. 
Eburnitis,  370,  457. 

healing  process  in,  376. 
Effects  of  arsenic  dioxide  and  metallic  arsenic 

upon  the  pulps  of  teeth,  518. 
Empyema  of  the  antrum,  542. 
Enamel,  absorption  of  the,  270. 

anomalies  of  the,  239. 

basis-substance  of  the,  91,96. 

beginning  formation  of  the,  170. 

boundary  between  dentine  and,  93. 

caries  of  the,  by  Abbott,  491. 

caries  of  the,  by  Miller,  503.  508. 

congenital  defects  in  the,  216. 

cuticle,  or  Nasmyth's  membrane,  43,  92. 

deficient  calcification  of  the,  210. 

fibrillie  of  the,  42,  90. 

first  trace  of  the  germ  of  the,  149. 

first  trace  of  the  tissue  of  the,  174. 

granulation  of  the,  214. 

growth  of  the,  180. 

living  matter  of,  90. 

minute  structure  of,  90,  96. 

nutrition  of  the,  270. 

of  devitalized  teeth,  273. 

physiology  of  the,  271. 

pigmentation  and  stratification  of  the,  45, 
207,  212. 

prisms  or  rods,  42. 

recalcification,  rehardening  of  the,  272. 

rods,  anomalous  arrangement  of  the,  209. 

sensitiveness  of  the,  272. 

striaj,  the,  of  Retzius,42. 

tumors  of  the,  ameloma,  554. 


672 


INDEX. 


Enamel-organ,  definition  of  the,  124. 

five  component  parts  of  the,  ]26. 

folds,  convolutions  and  reduplications  of 
the.  238. 

malformations  and  malpositions  of  the,  236, 

what  is  the  ultimate  fate  of  the,  174. 
Epithelioma,  or  dermoid  cancer,  604. 
Epithelium,  56. 

function  of,  58. 

of  glands,  58. 

varieties  of,  67. 
Erosion  of  teeth,  316. 
Eruption  of  teeth,  261. 

premature,  of  ill-developed  teeth.  233. 
Examination  for  carious  cavities  of  teeth,  282. 
External  epithelium  of  the  enamel-organ,  159, 
161,  165. 

breaking  up  of  the,  166. 

formation  of  blood-vessels  in,  166. 
External  oblique  line  of  lower  jaw,  10. 

Fatty  degeneration  of  the  pulp,  431. 
Faulty  development  of  the  teeth,  194. 

an  interesting  case  of,  198. 

time  of  occurrence  of,  196. 
Fibrous  connective  tissue,  general  description 

of,  48. 
Fusion  of  roots  of  teeth,  611. 

of  crowns  of  teeth,  611. 

of  two  teeth,  611. 

Gangrene  of  the  gums,  370. 

of  the  pulp,  dry,  396. 

of  the  pulp,  moist,  394. 
General  anatomy  of  the  human  teeth,  39. 
General  diagnosis  of  the  diseases  of  the  teeth, 

274. 
General  features  of  tumors,  546. 
General  histology,  46. 
Genial  tubercles,  10. 

Granuloma  in  hyperplastic  pericementitis,  472. 
Groove  for  facial  artery  of  lower  .iaw,  10. 
Gum,  acute  inflammation  of  the,  .364. 

anatomy  of  the,  40. 

chronic  inflammation  of  the,  366. 

diphtheritic  ulcers  of  the,  370. 

gangrene  of  the,  370. 

hyperaemia  of  the,  363. 

hyperplasia  of  the,  365. 

inflammation  of  the,  363. 

mucous  membrane  of  the,  41. 

papillary  layer  of  the,  41. 

syphilitic  ulceration  of  the.  369. 

the,  in  scurvy,  370. 

ulceration  of  the  (aphthae),  369. 

Healed  fracture  of  a  tooth,  612. 
Healing  process  in  caries,  516. 

in  cementitis,  487. 

in  eburnitis,  376. 

in  pericementitis,  475,  487. 
Heat  and  cold  in  general  diagnosis,  286. 
Herbst's  method  of  treatingjpulps,  524. 
Histology,  general,  46. 


Horizontal  or  inferior  turbinated  crest,  4. 
Hutchinson's  teeth,  194,  217. 
Hyperostosis  of  the  roots  of  teeth,  329. 

cause  of,  291,  329. 

circumscribed,  3.32. 

difi'used  with  roots  separated,  333. 

diffused  with  roots  united.  335. 

minute  anatomy  of  the,  338. 

union  of  two  teeth  by,  336,  611. 
Hyperplasia  in  general,  357. 

of  the  gums,  365. 

of  the  pericementum,  diffuse,  441. 

of  the  pericementum,  partial,  440. 

of  the  pulp,  partial.  389,  403. 

of  the  pulp,  total,  390,  407. 

Incisive  fossa  of  lower  jaw,  9. 

of  upper  jaw,  1. 
Incisor  teeth,  macroseopical  anatomy  of,  18,  19, 

26,  28. 
Individaal  characteristics  of  the  teeth,  24. 
Inferior  dental  canal,  11. 
Inferior  maxillary  bone,  9. 
Inflammation,  348. 

hyperplasia  in,  357. 

of  the  dentine,  eburnitis,  370. 

of  the  gums,  363. 

of  the  lymph-ganglia,  460. 

of  the  pericementum,  clinical  aspect,  432. 

of  the  pericementum,  morbid  anatomy,  462. 

of  the  pulp,  clinical  aspects  of,  380. 

of  the  pulp,  morbid  anatomy,  397. 

suppuration  in  the  process  of,  358. 
Infra-orbital  foramen,  1. 
Infra-orbital  groove,  2. 
Interglobular  spaces,  definition  of  the,  44. 

formation  of,  135. 
Internal  epithelium  of  enamel-organ,  159, 161. 
Internal  oblique  line  of  the  lower  jaw,  11. 
Interzonal  layer  between  dentine  and  enamel, 
81. 

betw.en  dentine  and  cement,  83. 
Involution  of  lower  maxilla,  12. 

of  upper  maxilla.  9. 
Irritation  and  new  formation  of  dental  tissues, 
288. 

and  new  formations  of  the  pulp,  289,  384. 

producing  hyperostosis  of  the  roots,  291. 

Jaw-bone,  lower,  9. 

necrosis  of  the,  534. 

upper,  1. 
Jaws,  tumors  of  the,  573. 

Lachetmal  or  nasal  duct,  4. 
Leueoplakia  oris,  369. 
Light  in  diagnosis,  281.  287. 
Lining  membrane  of  the  antrum,  7. 
Lobulation  of  crowns  of  teeth,  610. 
Lower  bicuspids,  macroseopical  anatomy  of,  20. 
central  incisors,  macroseopical  anatomy  of, 

19. 
cuspids  or  eye-teeth, macroseopical  anatomy 

of,  19. 


INDEX. 


673 


Lower  jaw-bone,  9. 

lateral  incisors,  macroscopical  anatomy  of, 
19. 

meatus  of  the  nasal  cavity,  i. 

molars,  macroscopical  anatomy  of,  22. 
Lymphadenitis,  460. 

Lymph-glands,  so-called,  structure  of  the,  58. 
Lymph-vessels,  structure  of  the,  58. 

of  the  pulp,  252. 

Malar  process,  2. 

Malformations  of  the  enamel-organ,  236. 

of  the  teeth,  609. 
Malpositions  of  teeth,  613. 
Maxillary  tuberosity,  2. 
Mechanical  abrasion,  309. 

secondary  dentine  in,  311. 
Medullary  cancer,  607. 
Mental  foramen,  10, 12. 
Mental  process,  9. 

Microscopical  features  of  abs.'ess  of  the  pulp, 
402. 
of  absorption  of  cementum  of  temporary 

teeth,  266. 
of    absorption   of  dentine    of   temporary 

teeth,  268. 
of  acute  caries  of  dentine  (Abbott),  496. 
of  acute  cementitis  and  pericementitis,  468. 
of  acute  non-purulent  pericementitis,  464, 

466. 
of  acute  non-purulent  pulpitis,  398,  400. 
of  acute  osteitis,  469,  470. 
of  acute  purulent  pulpitis,  402. 
of  acute  ulitis  (inflammation  of  the  gums), 

364. 
of  alveolar  abscess,  483,  484. 
of  alveolar  cysts,  563. 

of  amelitis  (inflammation  of  enamel),  322. 
of  ameloblasts,  172,  190,  193. 
of  atrophy  of  the  nerves  of  the    pulp,  427, 

428,  430. 
of  blood-  and  lymph-vessels  in  general,  57. 
of  blood-  and  lymph-vessels  of  the  pulp,  248, 

252. 
of  blood-vessels  of  the  pericementum,  260. 
of  calcification  of  the  pulp,  421,  422. 
of  cancellous  bone-tissue,  51. 
of  caries  of  cement  (Abbott).  501. 
of  caries  of  enamel  (Abbott),  492. 
of  cementum,  43,  103,  110. 
of  chronic  caries  of  dentine  (Abbott),  494, 

496. 
of  chronic  partial  hyperplasia  of  the  pulp, 

403,  404,  406. 
of  chronic  purulent  pulpitis,  409,  410. 
of  chronic  total  hyperplasia  of  the  pulp, 

307,  407. 
of   chronic    ulitis    Unflammation    of    the 

gums),  366. 
of  cortical  bone-tissue,  52. 
of  decay  of  cement  (Miller),  514. 
of  decay  of  dentine  (Miller),  510,  512,  513. 
of  decay  of  enamel  (Miller),  507,  509. 
of  dentine,  41,  73. 


Microscopical  features  of  development  of  bone- 
tissue,  65,  66. 
of  development  of  cementum.  228. 
of  development  of  dentine,  129-139. 
of  development  of  enamel,  148-180. 
of  development  of  enamel-organ,  the,  149- 

194. 
of  devitalized  cementum,  123. 
of  devitalized  dentine,  SO. 
of  dissolution  of  epithelial  cord,  the,  168, 

176. 
of  dissolution  of  external  epithelium,  165, 

167. 
of  dwarf  teeth,  236. 
of  eburnitis  (inflammation    of   dentine), 

370,  457. 
of  eifects  of  arsenic  (20  minutes).  521. 
of  effects  of  arsenic  (24  hours),  523,527, 

528. 
of  enamel,  the,  42,  90,  96. 
of  enamel-fibers,  the,  90,  96,  174. 
of  enamel-prisms,  the,  99. 
of  epithelial  tissue,  56. 
of  external  epithelium,  162. 
of  faulty  development  of  dentine,  205,  218, 

223,  242. 
of  faulty  development  of  enamel,  197,  201, 

218,  222,  239,  240. 
of  fibrous  connective  tissue,  49. 
of  fibrous  pericementum,  258. 
of  fibrous  pulp-tissue,  307, 530. 
of  gigantic  growths  (teratoma  of  the  teeth), 

S56. 
of  gum,  the,  41. 

of  healing  process  of  caries,  the,  517. 
of  healing  process  of  pericementitis    and 

cementitis,  487. 
of  hyperostosis  of  roots  of  teeth,  339-346. 
of  hyperplasia  of  the  gum,  367,  368. 
of  hyperplasia  of  the  pulp,  partial,  403-406. 
of  hyperplasia  of  the  pulp,  total,  307,  407. 
of  hyperplastic  pericementitis,  473,  475. 
of  internal  epithelium,  the,  162. 
of  interzonal  layer  between  deniine  and 

cementum,  83. 
of  interzonal  layer  between  dentine  and 

enamel,  93. 
of  lymph-vessels  of  the  pulp,  252. 
of  muscle-tissue,  53. 
of  myxomatous  pericementum,  256. 
of  myxomatous  tissue,  48. 
of  Nasmyth's  membrane,  43,  92. 
of  neck  of  the  tooth,  84, 105, 115, 119. 
of  necrosis  of  the  jaw-bones,  541. 
of  nerve-tissue,  55. 
of  nerves  of  the  pulp,  249,  253. 
of  normal  pericementum,  256-260. 
of  normal  pulp-tissue,  247-253. 
of  odontoblasts,  249,  253. 
of  odontoblasts  in  developing  dentine,  138, 

144, 146. 
of  protoplasm  in  general,  -58. 
of      purulent     marginal     pericementitis, 

(pyorrhoea  alveolaris),  478,  481. 


674 


INDEX. 


Microscopical  features  of  reaction  of  the  den- 
tine upon  atnalgam,  87,  326. 

of  reaction  of  the   dentine  upon  fillings, 
320. 

of  reaction  of  the  dentine  upon  gold,  322, 
324. 

of  reaction  of  the  dentine  upon  oxyphos- 
phate,  325. 

of  reaction  of  the  dentine  upon  tin,  529. 

of  reticular  atrophy  of  the  pulp,  425,  426. 

of  sclerotic  atrophy  of  the  pulp,  424. 

of  secondary  dentine  in  general,  289-308. 

of  secondary  dentine  in  mechanical  abra- 
sion, 311,  315. 

of  stellate  reticulum,  the,  164, 192, 193. 

of  stratification  and  pigmentation  of  the 
enamel,  45,  207,  211,  213. 

of  stratum  intermedium,  162, 192, 193. 

of  the  reticulum  of  cementum,  103-121. 

of  the  reticulum  of  dentine,  73-87,  89. 

of  the  reticulum  of  enamel,  91-99. 

of  tumors    of  the  cement  (osteoma),  339- 
346,  555. 

of  tumors  of  the  dentine  (odontoma),  553. 

of  tumors  of  the  enamel  (ameloma),  554. 

of  tumors  of  the  jaws,  573. 

of  tumors  of  the  pulp,  557. 
Microscopical  specimens,  preparation  of,  69, 128, 
244. 

Nasal  process  of  upper  jaw,  2. 
Neck  of  the  tooth,  structm-e  of  the,  83, 105, 119. 
Necrosis  of  the  jaw-bones,  534. 
Nerve-fibers,  general  description  of,  55. 
Nerve-tissue,  general  description  of,  55. 
Nerves  of  the  pulp,  253. 

calcification  of  the,  429. 
Nutrition  of  the  hard  dental  tissues,  271. 

Odontoblast  layer.  44,  249,  253. 

in  developing  dentine,  131, 139. 
Odontoma,  tumor  of  the  dentine,  553. 
Osteitis,  osteomyelitis,  periostitis,  458,  569. 
Osteoblasts,  257. 
OzEena  of  the  nose,  545. 

Palate  process  of  upper  jaw,  3. 
Percussion  in  diagnosis,  283. 

different  sounds  of,  284. 
Pericementum,  the,  39,  255. 

blood-vessels  of  the,  260. 

bony  new  formations  in  the,  475. 

minute  structure  of,  255. 

osteoblasts  of  the,  257. 

two  forms  of,  256. 
Pericementitis,  acute  non-purulent  apical,  436. 

acute  non-purulent  circumscribed,  434. 

acute  non-purulent  diffuse,  438. 

acute  non-purulent  marginal,  433. 

acute  purulent  apical,  442. 

acute  purulent  diffuse,  444. 

chronic  purulent  apical,  452. 

chronic    purulent     circumscribed     (blind 
abscess),  451. 


Pericementitis,  chronic  purulent  diffuse,  454. 
chronic  purulent  marginal  (pyorrhoea  al- 

veolaris),  445. 
classification  of,  432. 
clinical  aspects  of,  432. 
diffuse  hyperplastic,  441. 
morbid  anatomy  of,  462. 
partial  hyperplastic,  440. 
Periosteum  of  the  alveolus,  39. 
Periostitis,  osteitis,  osteomyelitis.  458,  569. 
Phj'sical  examination  in  diagnosis,  281. 
Physiology  of  the  hard  dental  tissues,  270. 

of  the  senile  changes  of  dental  tissues,  273. 
Pigmentation  of  the  enamel.  212. 
of  the  enamel  in  caries,  491,  507. 
of  the  pulp,  425,  431. 
Polypoid  growth  in  the  antrum,  543. 
Posterior  dental  canals,  1. 
Posterior  palatine  canal,  4. 
Pregnancy,  the  teeth  during,  277.  ' 
Premature  eruption  of  ill-developed  teeth,  233. 
Preparation  of  microscopical  specimens,  69, 128, 

244. 
Prognosis  of  acute  non-purulent  apical  peri- 
cementitis, 438. 
of  acute  non-purulent  circumscribed  peri- 
cementitis, 43 '). 
of  acute  non-purulent  difl'use  pericemen- 
titis, 439. 
of  acute  con-purulent  marginal  pericemen- 
titis, 431. 
of  acute  non-purulent  partial  pulpitis,  386. 
of  acute  non-purulent  total  pulpitis,  387. 
of  acute  purulent  apical  pericementitis,  443. 
of  acute  purulent  diffuse  pericementitis, 

445. 
of  acute  purulent  pulpitis,  389. 
of  calcification  of  the  pulp,  413. 
of  cementitis  and  eburnitis,  458. 
of  chronic  purulent  apical  pericementitis, 

453. 
of  chronic  purulent  circumscribed  perice- 
mentitis (blind  abscess),  452. 
of  chronic  purulent  diffuse  pericementitis, 

455. 
of  chronic  purulent  marginal  pericementitis 

(pyorrhoea  alveolaris),  450. 
of  chronic  purulent  pulpitis,  394. 
of  eburnifieations  and  ossifications  of  the 

pulp.  418. 
of  empyema  of  the  antrum, 545. 
of  gangrene  of  the  pulp,  dry,  397. 
of  gangrene  of  the  pulp,  moist,  396. 
of  hyperplasia  of  the  pulp,  partial,  390. 
of  hyperplastic  difi'use  pericementitis,  442. 
of  hyperplastic  partial  pericementitis,  441. 
of  irritation  of  the  pulp,  385. 
of  lymphadenitis,  461. 
of  necrosis  of  the  jaw-bones,  537. 
of  periostitis,  osteitis,  and  osteomyelitis, 

460. 
of  reticular  atrophy  of  the  pulp,  420. 
of  sclerotic  atrophy  of  the  pulp,  419. 
of  tumors  in  general,  550. 


INDEX. 


675 


Pulp  of  a  tooth,  the,  43,  244. 

blood-vessels  of  the,  43,  44,  246. 

formations  of  dentine  and  bone  in  the,  289, 
305. 

irritation  of  the,  289,  384. 

lymphatics  of  the,  252. 

method  of  preparing  sections  of  the,  244. 

minute  structure  of  the,  246. 

nerves  of  the,  253. 

new  formations  in  the,  305. 

odontoblasts  of  the,  44,  249,  2-53. 

the  Herbst  method  of  treating  exposed,  524. 

tumors  of  the,  550. 
Pulp-chambers  of  the  teeth,  28. 

measurements  of  the,  31.  32,  33. 
Pulp-stones  composed  of  secondary  dentine,  305. 

composed  of  laminated  bone,  306. 

composed  of  a  mixture  of  regular  bone  and 
dentine,  307. 

composed  of  primary  dentine,  308. 
Pulpitis,  acute  non-purulent,  partial,  385. 

acute  non-purulent,  total,  38t. 

acute  purulent,  387. 

chronic  purulent,  392. 

clinical  aspects  of,  380. 

etiology  of,  380. 

hyperplastic,  partial,  389. 

hyperplastic,  total,  390. 

morbid  anatomy.of,  -397. 
Pyorrhoea  alveolaris,  445. 

morbid  anatomy  of,  476. 

Reaction  of  the  dentine  upon  amalgam,  87, 
326. 

upon  fillings,  320. 

upon  gold,  323. 

upon  gutta-percha,  323. 

upon  oxyphosphate  of  zinc,  323. 
Reealcification  of  softened  enamel  and  dentine, 

272. 
Re-formation  of  cementum,  487. 
Reticular  atrophy  of  the  pulp,  419,  425. 
Roots  of  teeth,  devious  course  of,  610. 

fusion  of,  611. 

hyperostosis  or  hyperplasia  of  the,  329. 

macroscopical  anatomy  of  the,  18. 

multiplication  of,  611. 

Salivary  calculi,  275,  448. 

SclerotiL-  atrophy  of  the  pulp,  418.  442. 

Secondary  dentine,  292. 

in  the  middle  of  the  pulp-tissue,  305. 

in  mechanical  abrasion,  311. 

similar  to  primary  dentine,  299,  308. 

varieties  of,  298. 

with  Haversian  canals  (vaso-dentine),  303. 

with  lamellae,  302. 
Senile  changes  in  the  dental  tissues,  273. 
SmeU,  the  sense  of  in  diagnosis,  285. 
Sounds  produced  by  percussion  upon  the  teeth, 

284. 
Stellate  reticulum  and  stratum  intermedium 

126, 161, 163. 
Stratification  of  dentine,  136. 

of  enamel,  207. 


Subjective  phenomena  of  acute  non-purulent 
apical  pericementitis,  437. 

of  acute  non-purulent  circumscribed  peri- 
cementitis, 435. 

of  acute  non- purulent  diffuse  pericemen- 
titis, 439. 

of    acute  non-purulent    marginal    perice- 
mentitis, 433. 

of  acute  non-purulent  partial  pulpitis,  385. 

of  acute  non-purulent  total  pulpitis,  386. 

of  acute    purulent    apical  pericementitis, 
443. 

of  acute  purulent  diffuse  pericementitis, 
444. 

of  acute  purulent  pulpitis,  388. 

of  calcification  of  the  pulp,  413. 

of  chronic  alveolar  abscess,  456. 

of  chronic  hyperplastic  partial  pericemen- 
titis, 440. 

of  chronic  hyperplastic  total  pericementi- 
tis, 442. 

of  chronic  purulent  apical  pericementitis, 
453. 

of  chronic  purulent  circumscribed  perice- 
mentitis, 452. 

of  chronic  purulent  diffuse  pericementitis, 
454. 

of  chronic  purulent  marginal  pericementi- 
tis, 449. 

of  chronic  purulent  pulpitis,  393. 

of  eburnifications  and  ossifications  of  the 
pulp,  416. 

of  empyema  of  the  antrum,  544. 

of  gangrene  of  the  pulp,  dry,  396. 

of  gangrene  of  the  pulp,  moist,  395. 

of  hyperplasia  of  the  pulp,  partial,  390. 

of  hyperplasia  of  the  pulp,  total,  391. 

of  irritation  of  the  pulp,  384. 

of  lymphadenitis,  461. 

of  necrosis  of  the  jaw-bones,  536. 

of  periostitis,  osteitis,  and    osteomyelitis, 
459. 

of  reticular  atrophy  of  the  pulp,  420. 
Sublingual  fossa,  10. 
Submaxillary  fossa,  11. 
Superior  maxillary  bones,  1. 
Supernumerary  teeth,  610. 
Synopsis  of  the   development   of  the   teeth, 

124. 
Syphilitic  ulcers  upon  the  gum,  369. 
Systemic  derangements  diagnosed  by  the  teeth 
and  their  surroundings,  275. 

Tartar  in  diagnosis,  275. 

forms  of,  275. 

green,  276. 

in  pregnancy,  277. 

in  pyorrhoea  alveolaris,  448. 

white  and  yellow,  275. 
Teeth,  anomalies  of  the  papilla  of  the,  242. 

and  gums  as    indicators    of  the    general 
health,  275. 

breach  of  the  continuity  of  the  crown  of, 
612. 


676 


INDEX. 


Teeth,  changes  of  the  tissues  of,  by  general  dis- 
eases, 278. 

description  of  their  surfaces,  17. 

devious  course  of  roots  of,  610. 

discoloration  of  devitalized,  273. 

distinguishing  features   between  the  per- 
manent and  temporary,  24. 

distinguishing  features  between  the  upper 
and  lower,  25. 

double  papillae  of,  235. 

dwarf,  235,  609. 

faulty  development  of,  194. 

forms  of,  16. 

fusion  of  crowns  of,  611. 

fusion  of  roots  of,  611. 

fusion  of  two,  611. 

healed  fracture  of,  612. 

hyperplasia,  or  hyperostosis  of  the  roots  of, 
329,  609. 

individual  characteristics  of  the,  24. 

lobulation  of  the  crowns  of,  610. 

macroscopical  description  of  the,  16. 

malformations  of,  609. 

malpositions  of  the,  613. 

multiplication  of  roots  of,  611. 

numbering  of  the,  25. 

percussion  in  diseases  of  the,  283. 

supernumerary,  610. 

syphilitic  or  Hutchinson's,  194,  217. 
Teratoma  of  teeth,  or  gigantic  growth,  556. 
Tissue,  bony  or  osseous,  49. 

cartilaginous,  49. 

connective,  46. 

epithelial,  56. 

fibrous,  48. 

general  description  of,  46. 

muscle,  52. 

myxomatous,  47. 

nerve,  55. 
Touch,  the  sense  of  in  diagnosis,  281. 
Transillumination  in  diagnosis,  287. 
Tumors,  their  clinical  and  anatomical  features 
in  general,  546. 

ameloma,  of  the  enamel,  554. 

classification  of,  550. 

covering  skin  or  mucosa  of,  547. 


Tumors,  definition  of,'546. 

demarkation  of,  547. 

diagnosis  of,  549. 

etiology  of,  546. 

growth,  benignity  and  malignity  of,  546. 

hyperplasia  of  the  roots  of,  329,  555. 

infection  of  remote  tissues  and  organs  by, 
548. 

odontoma,  of  the  dentine,  553. 

of  the  pulp,  lymphomyeloma,  557. 

of  the  pulp,  myeloma,  556. 

of  the  teeth,  553. 

pain  of,  547. 

prognosis  of,  550. 

reaction  upon  adjacent  tissues,  547. 

teratoma,  or  gigantic  growth,  556. 

ulceration  of  the  surface  of,  548. 
Tumors  of  the  jaws,  angioma.  584. 

carcinoma  or  cancer,  604. 

cavernous  angioma,  587. 

chrondroma,  582. 

cysto-adenoma,  601. 

epithelioma  or  dermoid  cancer,  604. 

fibro-myeloma,  591. 

fibroma,  577. 

globo-myeloma,  597. 

lipo-fibroma,  582. 

lobular  angioma,  584. 

medullary  cancer,  607. 

myeloma,  589. 

myxoma,  573. 

myxo-fibroma,  575. 

myxo-myeloma,  590. 

osteoma  of  jaws,  581. 

osteoma  of  roots,  329,  555. 

osteo-myeloma,  595. 

papilloma  or  warty  tumor,  599.' 

spindle  myeloma,  598. 

Upper  central  incisors,  18. 

bicuspids.  20. 

cuspids  or  eye-teeth,  19. 

lateral  incisors,  18. 

molars,  21. 
Ulitis,  acute  inflammation  of  the  gums,  363. 

chronic  inflammation  of  the  gums,  366. 


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